Physical Review Materials最新文献

{"title":"Effect of local chain stiffness on oligomer crystallization from a melt","authors":"Pierre Kawak, Christopher Akiki, Douglas R. Tree","doi":"10.1103/physrevmaterials.8.075606","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.075606","url":null,"abstract":"While the process by which a polymer crystal nucleates from the melt has been extensively studied via molecular simulation, differences in polymer models and simulated crystallization conditions have led to seemingly contradictory results. We make steps to resolve this controversy by computing low-temperature phase diagrams of oligomer melts using Wang-Landau Monte Carlo simulations. Two qualitatively different crystallization mechanisms are possible depending on the local bending stiffness potential. Polymers with a discrete bending potential crystallize via a single-step mechanism, whereas polymers with a continuous bending potential can crystallize via a two-step mechanism that includes an intermediate nematic phase. Other model differences can be quantitatively accounted for using an effective volume fraction and a temperature scaled by the bending stiffness. These results suggest that at least two universality classes of nucleation exist for melts and that local chain stiffness is a key determining factor in the mechanism of nucleation.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"99 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141754128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probing intrinsic magnetization dynamics of the Y3Fe5O12/Bi2Te3 interface at low temperature","authors":"A. R. Will-Cole, Valeria Lauter, Alexander Grutter, Carsten Dubs, David A. Lidsky, Morris Lindner, Timmy Reimann, Nirjhar Bhattacharjee, Tzu-Ming Lu, Peter Sharma, Nichole R. Valdez, Charles J. Pearce, Todd C. Monson, Matthew Matzelle, Arun Bansil, Don Heiman, Nian X. Sun","doi":"10.1103/physrevmaterials.8.074409","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.074409","url":null,"abstract":"Topological insulator–magnetic insulator (TI–MI) heterostructures hold significant promise in the field of spintronics, offering the potential for manipulating magnetization through topological surface state–enabled spin-orbit torque. However, many TI–MI interfaces are plagued by issues such as contamination within the magnetic insulator layer and the presence of a low-density transitional region of the topological insulator. These interfacial challenges often obscure the intrinsic behavior of the TI–MI system. In this study, we addressed these challenges by depositing sputtered <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Bi</mi><mn>2</mn></msub><msub><mi>Te</mi><mn>3</mn></msub></mrow></math> on liquid phase epitaxy grown <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">Y</mi><mn>3</mn></msub><msub><mi>Fe</mi><mn>5</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>12</mn></msub><mo>/</mo><msub><mi>Gd</mi><mn>3</mn></msub><msub><mi>Ga</mi><mn>5</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>12</mn></msub></mrow></math>. The liquid phase epitaxy grown <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">Y</mi><mn>3</mn></msub><msub><mi>Fe</mi><mn>5</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>12</mn></msub></mrow></math> has been previously shown to have exceptional interface quality, without an extended transient layer derived from interdiffusion processes of the substrate or impurity ions, thereby eliminating rare-earth impurity-related losses in the MI at low temperatures. At the TI–MI interface, high-resolution depth-sensitive polarized neutron reflectometry confirmed the absence of a low-density transitional growth region of the TI. By overcoming these undesirable interfacial effects, we isolate and probe the intrinsic low-temperature magnetization dynamics and transport properties of the TI–MI interface. Our findings revealed strong spin pumping at low temperatures, accompanied by an additional in-plane anisotropy. The enhanced spin pumping at low temperatures is correlated with the observed suppression of bulk conduction and the weak antilocalization in the TI film, highlighting the interplay between the transport and spin pumping behavior in the TI–MI system.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"43 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141754124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nodal line induced large transverse thermoelectric response in the D03-type Heusler compound Fe3Si","authors":"Susumu Minami, Sota Hogaki, Takahiro Shimada","doi":"10.1103/physrevmaterials.8.075403","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.075403","url":null,"abstract":"Giant magnetic transverse thermoelectric effect, anomalous Nernst effect (ANE), was theoretically and experimentally observed in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>3</mn><mi>d</mi></mrow></math>-transition metal compounds. The intrinsic components of ANE can be described from the electronic structure based on the Berry phase concept. The topological electronic structure, such as the Weyl node and nodal lines, induces large Berry curvature, one origin of giant ANE. We investigated transverse thermoelectric properties on ferromagnetic <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">D</mi><msub><mn>0</mn><mn>3</mn></msub></mrow></math>-type Heusler compounds <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Fe</mi><mn>3</mn></msub><mi>Si</mi></mrow></math> based on first-principles calculations. We found large transverse thermoelectric conductivity <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>α</mi><mrow><mi>x</mi><mi>y</mi></mrow></msub><mo>∼</mo><mn>5</mn><mspace width=\"4pt\"></mspace><msup><mrow><mi>AK</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><msup><mrow><mi mathvariant=\"normal\">m</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> is realized with hole carrier doping at room temperature. We also clarified that the nodal line and its stationary point enhance transverse thermoelectric conductivity. These results give us a clue to design high-performance ANE-based magnetic thermoelectric materials.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"43 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141754096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Possible Wigner states in CrI3 heterostructures with graphene: A tight-binding model perspective","authors":"Igor Rozhansky, Vladimir Fal'ko","doi":"10.1103/physrevmaterials.8.074007","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.074007","url":null,"abstract":"In this study, we present an effective tight-binding model for an accurate description of the lowest energy quadruplet of a conduction band in a ferromagnetic <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cr</mi><msub><mi>X</mi><mn>3</mn></msub></mrow></math> monolayer, tuned to the complementary <i>ab initio</i> density functional theory simulations. This model, based on a minimum number of chromium orbitals, captures a distinctively flat dispersion in those bands but requires taking into account hoppings beyond nearest neighbors, revealing ligand-mediated electron pathways connecting remote chromium sites. Doping of states in the lowest conduction band of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cr</mi><msub><mi>X</mi><mn>3</mn></msub></mrow></math> requires charge transfer, which, according to recent studies [Tenasini <i>et al.</i>, <span>Nano Lett.</span> <b>22</b>, 6760 (2022); Tseng <i>et al.</i>, <span>Nano Lett.</span> <b>22</b>, 8495 (2022); Cardoso <i>et al.</i>, <span>Phys. Rev. B</span> <b>108</b>, 184423 (2023)], can occur in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mrow><mi>graphene</mi><mo>(</mo><mi mathvariant=\"normal\">G</mi><mo>)</mo></mrow><mo>/</mo><mi>Cr</mi><msub><mi>X</mi><mn>3</mn></msub></mrow></math> heterostructures. Here, we use the detailed description of the lowest conduction band in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>CrI</mi><mn>3</mn></msub></math> to show that <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">G</mi><mo>/</mo><msub><mi>CrI</mi><mn>3</mn></msub><mo>/</mo><mi mathvariant=\"normal\">G</mi></mrow></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">G</mi><mo>/</mo><msub><mi>CrI</mi><mn>3</mn></msub></mrow></math> are type-II heterostructures where light holes in graphene would coexist with heavy electrons in the magnetic layer, where the latter can be characterized by Wigner-Seitz radius <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>r</mi><mi>s</mi></msub><mo>∼</mo><mn>25</mn><mo>−</mo><mn>35</mn></mrow></math> (as estimated for hBN-encapsulated structures).","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"20 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141754122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proximate Tomonaga-Luttinger liquid in a spin-1/2 ferromagnetic XXZ chain compound","authors":"Boqiang Li, Xun Chen, Yuqian Zhao, Zhaohua Ma, Zongtang Wan, Yuesheng Li","doi":"10.1103/physrevmaterials.8.074410","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.074410","url":null,"abstract":"The spin-<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math> ferromagnetic XXZ chain is a prototypical many-body quantum model, exactly solvable via the integrable Bethe ansatz method, hosting a Tomonaga-Luttinger spin liquid. However, its clear experimental realizations remain absent. Here, we present a thorough investigation of the magnetism of the structurally disorder-free compound <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>LuCu</mi><msub><mrow><mo>(</mo><mi>OH</mi><mo>)</mo></mrow><mn>3</mn></msub><msub><mi>SO</mi><mn>4</mn></msub></mrow></math>. By conducting magnetization and electron-spin-resonance measurements on the single-crystal sample, we establish that the title compound approximates the spin-<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math> ferromagnetic XXZ chain model with a nearest-neighbor exchange strength of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>J</mi><mn>1</mn></msub><mo>∼</mo><mn>65</mn><mspace width=\"0.16em\"></mspace><mi mathvariant=\"normal\">K</mi></mrow></math> and an easy-plane anisotropy of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>∼</mo><mn>0.994</mn></mrow></math>. The specific heat demonstrates a distinctive power-law behavior at low magnetic fields (with energy scales <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>≤</mo><mn>0.02</mn><msub><mi>J</mi><mn>1</mn></msub></mrow></math>) and low temperatures <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mi>T</mi><mo>≤</mo><mn>0.03</mn><msub><mi>J</mi><mn>1</mn></msub><mo>)</mo></mrow></math>. This behavior is consistent with the expectations of the ideal spin-<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math> ferromagnetic XXZ chain model, thereby supporting the formation of a gapless Tomonaga-Luttinger spin liquid in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>LuCu</mi><msub><mrow><mo>(</mo><mi>OH</mi><mo>)</mo></mrow><mn>3</mn></msub><msub><mi>SO</mi><mn>4</mn></msub></mrow></math>.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"65 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141754127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probing the interface and individual layers in cuprate/manganite heterostructures by Raman spectroscopy","authors":"F. Lyzwa, A. Chan, K. Fürsich, B. Keimer, C. Faugeras, Yu. G. Pashkevich, C. Bernhard, M. Minola, B. P. P. Mallett","doi":"10.1103/physrevmaterials.8.074804","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.074804","url":null,"abstract":"We report a comprehensive set of polarized Raman spectra on thin-film multilayers of the high-<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>T</mi><mi>c</mi></msub></math> superconductor <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mrow><mi>YBa</mi></mrow><mn>2</mn></msub><msub><mrow><mi>Cu</mi></mrow><mn>3</mn></msub><msub><mrow><mi mathvariant=\"normal\">O</mi></mrow><mn>7</mn></msub></math> and electrically insulating manganites <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>R</mi><msub><mi>MnO</mi><mn>3</mn></msub></mrow></math> (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>R</mi><mo>=</mo></mrow></math> rare-earth partially substituted with group-II elements) hosting magnetic, charge and orbital order (COO). Such multilayers have been shown to exhibit a unique insulating-to-superconducting transition that is induced by magnetic field, electric field, or by tailoring the chemical composition of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> site of the manganite. The Raman spectra show significant Jahn-Teller distortions of the manganite structure, which correlate with COO, approximately 90 K above the magnetic ordering temperature of 140 K. Based on the Raman data and earlier electrical transport studies of single-layer manganite films, we argue that the manganite layers in our heterostructures remain electrically insulating across the range of investigated temperatures, dopings, and magnetic fields. The Raman spectra show a pronounced redshift and broadening of lattice vibrations around 200 <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> in the multilayers compared to those of manganite films, which may indicate hybridization with <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mrow><mi>YBa</mi></mrow><mn>2</mn></msub><msub><mrow><mi>Cu</mi></mrow><mn>3</mn></msub><msub><mrow><mi mathvariant=\"normal\">O</mi></mrow><mn>7</mn></msub></math> phonons. We also observe additional excitations at 690 <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> and 830 <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> that are absent in the single films or bulk responses, which we discuss to originate from the cuprate/manganite interface. These observations demonstrate that the phonon spectrum is significantly modified in our multilayer samples. This is expected to play an important role in the mechanism of the insulating-to-superconducting transition found in these cuprate-manganite multilayers.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"39 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tetragonal phases in Fe-Ga alloys: A quantitative study","authors":"A. M. Balagurov, I. A. Bobrikov, D. Yu. Chernyshov, A. S. Sohatsky, S. V. Sumnikov, B. Yerzhanov, I. S. Golovin","doi":"10.1103/physrevmaterials.8.073604","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.073604","url":null,"abstract":"Currently, the dominant model for the formation of enhanced magnetostriction of Fe-Ga alloys is based on the assumption of the presence of microscopic inclusions with a tetragonal <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>L</mi><msub><mn>6</mn><mn>0</mn></msub></mrow></math> structure in the cubic matrix of the alloy. However, no evidence for the presence of this phase in the bulk of the alloys in amounts sufficient to have a noticeable effect on the magnitude of magnetostriction has been obtained so far. To test this hypothesis, a detailed scanning of the reciprocal space of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">F</mi><msub><mi mathvariant=\"normal\">e</mi><mn>81</mn></msub><mi mathvariant=\"normal\">G</mi><msub><mi mathvariant=\"normal\">a</mi><mn>19</mn></msub><mi mathvariant=\"normal\">T</mi><msub><mi mathvariant=\"normal\">b</mi><mrow><mn>0.1</mn></mrow></msub></mrow></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Fe</mi><mn>73</mn></msub><msub><mi>Ga</mi><mn>27</mn></msub></mrow></math> single crystals was carried out at ESRF at high photon flux stations. In particular, it was possible to reliably record superstructure diffraction peaks, the intensity of which was at a level of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></math> from the intensity of the fundamental peaks. Nevertheless, neither the presence of superstructure diffraction peaks obviously belonging to the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>L</mi><msub><mn>6</mn><mn>0</mn></msub></mrow></math> phase nor the tetragonal splitting of the fundamental diffraction peaks into components, which could indicate the presence of this phase in the samples, was detected. Similar results were obtained using complementary methods (electron and neutron diffraction). Based on the performed analysis of the background level in the places of the expected positions of superstructure peaks of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>L</mi><msub><mn>6</mn><mn>0</mn></msub></mrow></math> phase, it was found that the volume fraction of this phase in the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">F</mi><msub><mi mathvariant=\"normal\">e</mi><mn>81</mn></msub><mi mathvariant=\"normal\">G</mi><msub><mi mathvariant=\"normal\">a</mi><mn>19</mn></msub><mi mathvariant=\"normal\">T</mi><msub><mi mathvariant=\"normal\">b</mi><mrow><mn>0.1</mn></mrow></msub></mrow></math> alloy cannot exceed 0.2 %. The presence of a previously discovered <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>X</mi></math> phase with hexagonal or orthorhombic symmetry in a crystal with 27 at. % Ga was confirmed.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"7 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tuning the electronic and magnetic states of Ca2RuO4 with proton evolution","authors":"Di Tian, Ludi Miao, Liang Si, Nathaniel J. Schreiber, Shengchun Shen, Jianbing Zhang, Xinyu Shu, Xiaochao Wang, Hari P. Nair, Jacob P. Ruf, Darrell G. Schlom, Kyle M. Shen, Pu Yu","doi":"10.1103/physrevmaterials.8.074408","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.074408","url":null,"abstract":"With strong correlations between lattice, spin, and charge degrees of freedom, the layered ruthenate <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">C</mi><msub><mi mathvariant=\"normal\">a</mi><mn>2</mn></msub><mi>Ru</mi><msub><mi mathvariant=\"normal\">O</mi><mn>4</mn></msub></mrow></math> has attracted considerable interest over the past few decades due to its metal-insulator transition, antiferromagnetic-to-ferromagnetic transition, metamagnetic transition, and orbital ordering. Much effort has been devoted to manipulating its crystalline structure through epitaxial strain, chemical substitution, and pressure to clarify the underlying many-body physics and related quantum critical phenomena. Here we report a comprehensive proton intercalation study of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">C</mi><msub><mi mathvariant=\"normal\">a</mi><mn>2</mn></msub><mi>Ru</mi><msub><mi mathvariant=\"normal\">O</mi><mn>4</mn></msub></mrow></math> thin films and investigate their magneto-transport properties arising from structural deformations and carrier doping. It reveals a rich phase diagram with distinct electronic and magnetic ground states. Specifically, with increasing gate voltage during ionic liquid gating, the film first evolves from an insulating state into a metallic state and then gradually turns towards an exotic Mott insulator. Furthermore, we observed an emergent metamagnetic transition from a canted antiferromagnetic to a nearly ferromagnetic state, a characteristic feature conventionally triggered by external magnetic field, but here with electron doping. Our first-principles calculations reveal that these unexpected features could be attributed to the proton evolution-induced synergistic structural distortion and electron doping during ionic liquid gating. Our findings highlight the important role of both lattice and charge degrees of freedom in the intriguing electronic states of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">C</mi><msub><mi mathvariant=\"normal\">a</mi><mn>2</mn></msub><mi>Ru</mi><msub><mi mathvariant=\"normal\">O</mi><mn>4</mn></msub></mrow></math> and provide an effective approach to uncover different properties in quantum materials.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"57 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical properties of metallic MXene multilayers through advanced first-principles calculations","authors":"Zafer Kandemir, Pino D'Amico, Giacomo Sesti, Claudia Cardoso, Milorad V. Milošević, Cem Sevik","doi":"10.1103/physrevmaterials.8.075201","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.075201","url":null,"abstract":"Having a strong electromagnetic absorption, MXene multilayers are readily envisaged for applications in electromagnetic shields and related prospective technology. However, an <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"italic\">ab</mi></mrow></math> <i>initio</i> characterization of the optical properties of MXenes is still lacking, due in part to major difficulties with the treatment of metallicity in the first-principles approaches. Here we addressed the latter challenge, after a careful treatment of intraband transitions, to present a thorough analysis of the electronic and optical properties of a selected set of metallic MXene layers based on density functional theory (DFT) and many-body perturbation theory calculations. Our results reveal that the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"italic\">GW</mi></mrow></math> corrections are particularly important in regions of the band structure where <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"italic\">d</mi></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"italic\">p</mi></math> states hybridize. For some systems, we show that <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"italic\">GW</mi></mrow></math> corrections open a gap between occupied states, resulting in a band structure that closely resembles that of an intrinsic transparent conductor, thereby opening an additional line of prospective applications for the MXenes family. Nevertheless, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"italic\">GW</mi></mrow></math> and Bethe-Salpeter corrections have a minimal influence on the absorption spectra, in contrast to what is typically observed in semiconductor layers. Our present results suggest that calculations within the independent particle approximation (IPA) calculations are sufficiently accurate for assessing the optical characteristics of bulk-layered MXene materials. Finally, our calculated dielectric properties and absorption spectra, in agreement with existing experimental data, confirm the potential of MXenes as effective infrared emitters.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"33 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-mem behavior at reduced voltages in La1/2Sr1/2Mn1/2Co1/2O3−x perovskite modified with Sm:CeO2","authors":"Wilson Román Acevedo, Myriam H. Aguirre, Beatriz Noheda, Diego Rubi","doi":"10.1103/physrevmaterials.8.075003","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.075003","url":null,"abstract":"The use of machine learning algorithms is exponentially growing and concerns are being raised about their sustainability. Neuromorphic computing aims to mimic the architecture and the information processing mechanisms of the mammalian brain, appearing as the only avenue that offers significant energy savings compared to the standard digital computers. Memcapacitive devices, which can change their capacitance between different nonvolatile states upon the application of electrical stimulation, can significantly reduce the energy consumption of bio-inspired circuitry. In the present work, we study the multi-mem (memristive and memcapacitive) behavior of devices based on thin films of the topotactic redox <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">L</mi><msub><mi mathvariant=\"normal\">a</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub><mi mathvariant=\"normal\">S</mi><msub><mi mathvariant=\"normal\">r</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub><mi mathvariant=\"normal\">M</mi><msub><mi mathvariant=\"normal\">n</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub><mi mathvariant=\"normal\">C</mi><msub><mi mathvariant=\"normal\">o</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub><msub><mi mathvariant=\"normal\">O</mi><mrow><mn>3</mn><mo>−</mo><mi>x</mi></mrow></msub></mrow></math> (LSMCO) perovskite modified with Sm:<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Ce</mi><msub><mi mathvariant=\"normal\">O</mi><mn>2</mn></msub></mrow></math> (SCO), grown on Nb:<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>SrTiO</mi><mn>3</mn></msub></math> with (001) and (110) out-of-plane orientations. Either the self-assembling at the nanoscale of both LSMCO and SCO phases or the doping with Ce(Sm) of the LSMCO perovskite were observed for different fabrication conditions and out-of-plane orientations. The impact of these changes on the device electrical behavior was determined. The optimum devices resulted those with (110) orientation and Ce(Sm) doping the perovskite. These devices displayed a multi-mem behavior with robust memcapacitance and significantly lower operation voltages (especially the reset voltage) in comparison with devices based on pristine LSMCO. In addition, they were able to endure electrical cycling—and the concomitant perovskite topotactic redox transition between oxidized and reduced phases—without suffering nanostructural changes nor cationic segregation. We link these properties to an enhanced perovskite reducibility upon Ce(Sm) doping. Our work contributes to increasing the reliability of LSMCO-based multi-mem systems and to reducing their operating voltages closer to the 1 V threshold, which are key issues for the development of nanodevices for neuromorphic or in-memory computing.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"13 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}