Journal of Physics: Materials最新文献

{"title":"2024 Roadmap on 2D Topological Insulators","authors":"Bent Weber, Michael Fuhrer, X.-L. Sheng, Shengyuan A. Yang, R. Thomale, S. Shamim, L. Molenkamp, David H Cobden, D. Pesin, H. Zandvliet, P. Bampoulis, Ralph Claessen, Fabian Menges, J. Gooth, Claudia Felser, C. Shekhar, Anton Tadich, Mengting Zhao, M. Edmonds, Junxiang Jia, Maciej Bieniek, J. Väyrynen, D. Culcer, Bhaskaran Muralidharan, Muhammad Nadeem","doi":"10.1088/2515-7639/ad2083","DOIUrl":"https://doi.org/10.1088/2515-7639/ad2083","url":null,"abstract":"\u0000 2D topological insulators promise novel approaches towards electronic, spintronic, and quantum device applications. This is owing to unique features of their electronic band structure, in which bulk-boundary correspondences enforces the existence of 1D spin-momentum locked metallic edge states – both helical and chiral – surrounding an electrically insulating bulk. Forty years since the first discoveries of topological phases in condensed matter, the abstract concept of band topology has sprung into realization with several materials now available in which sizable bulk energy gaps – up to a few hundred meV – promise to enable topology for applications even at room-temperature. Further, the possibility of combing 2D TIs in heterostructures with functional materials such as multiferroics, ferromagnets, and superconductors, vastly extends the range of applicability beyond their intrinsic properties. While 2D TIs remain a unique testbed for questions of fundamental condensed matter physics, proposals seek to control the topologically protected bulk or boundary states electrically, or even induce topological phase transitions to engender switching functionality. Induction of superconducting pairing in 2D TIs strives to realize non-Abelian quasiparticles, promising avenues towards fault-tolerant topological quantum computing. This roadmap aims to present a status update of the field, reviewing recent advances and remaining challenges in theoretical understanding, materials synthesis, physical characterization and, ultimately, device perspectives.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139612408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extreme in-plane thermal conductivity anisotropy in Rhenium-based dichalcogenides","authors":"Sina Tahbaz, Simone Pisana","doi":"10.1088/2515-7639/ad1d8b","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1d8b","url":null,"abstract":"Anisotropies in thermal conductivity are important for thermal management in a variety of applications, but also provide insight on the physics of nanoscale heat transfer. As materials are discovered with more extreme transport properties, it is interesting to ask what the limits are for how dissimilar the thermal conductivity can be along different directions in a crystal. Here we report on the thermal properties of rhenium-based transition metal dichalcogenides (TMDs), specifically rhenium disulfide (ReS₂) and rhenium diselenide (ReSe₂), highlighting their extraordinary thermal conductivity anisotropy. Along the basal crystal plane of ReS₂, a maximum of <inline-formula>\u0000<tex-math><?CDATA $169pm11$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>169</mml:mn><mml:mo>±</mml:mo><mml:mn>11</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"jpmaterad1d8bieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> W mK⁻¹ is detected along the <italic toggle=\"yes\">b</italic>-axis and a minimum of <inline-formula>\u0000<tex-math><?CDATA $53pm4$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>53</mml:mn><mml:mo>±</mml:mo><mml:mn>4</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"jpmaterad1d8bieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> W mK⁻¹ perpendicular to it. For ReSe₂, the maximum and minimum values of <inline-formula>\u0000<tex-math><?CDATA $116pm3$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>116</mml:mn><mml:mo>±</mml:mo><mml:mn>3</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"jpmaterad1d8bieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> W mK⁻¹ and <inline-formula>\u0000<tex-math><?CDATA $27pm1$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>27</mml:mn><mml:mo>±</mml:mo><mml:mn>1</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"jpmaterad1d8bieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> W mK⁻¹ are found to lie 60° and 150° away from the <italic toggle=\"yes\">b</italic>-axis, along the polarization direction of some of the principal Raman modes. These measurements demonstrate a remarkable anisotropy of 3.2 × and 4.3 × in the conductivity <italic toggle=\"yes\">within</italic> the crystal basal planes, respectively. The through-plane thermal conductivities, recorded at <inline-formula>\u0000<tex-math><?CDATA $0.66pm0.01$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>0.66</mml:mn><mml:mo>±</mml:mo><mml:mn>0.01</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"jpmaterad1d8bieqn5.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> W mK⁻¹ for ReS₂ and <inline-formula>\u0000<tex-math><?CDATA $2.31pm0.01$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>2.31</mml:mn><mml:mo>±</mml:mo><mml:mn>0.01</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"jpmaterad1d8bieqn6.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> W mK⁻¹ for ReSe₂, highlight the impact of their laye","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139506367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hamiltonian learning with real-space impurity tomography in topological moiré superconductors","authors":"Maryam Khosravian, Rouven Koch, Jose L Lado","doi":"10.1088/2515-7639/ad1c04","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1c04","url":null,"abstract":"Extracting Hamiltonian parameters from available experimental data is a challenge in quantum materials. In particular, real-space spectroscopy methods such as scanning tunneling spectroscopy allow probing electronic states with atomic resolution, yet even in those instances extracting the effective Hamiltonian is an open challenge. Here we show that impurity states in modulated systems provide a promising approach to extracting non-trivial Hamiltonian parameters of a quantum material. We show that by combining the real-space spectroscopy of different impurity locations in a moiré topological superconductor, modulations of exchange and superconducting parameters can be inferred via machine learning. We demonstrate our strategy with a physically-inspired harmonic expansion combined with a fully-connected neural network that we benchmark against a conventional convolutional architecture. We show that while both approaches allow extracting exchange modulations, only the former approach allows inferring the features of the superconducting order. Our results demonstrate the potential of machine learning methods to extract Hamiltonian parameters by real-space impurity spectroscopy as local probes of a topological state.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139506166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-Temperature Crosslinked Soluble Polyimide as a Dielectric for Organic Thin-Film Transistors: Enhanced Electrical Stability and Performance","authors":"Sungmi Yoo, K. Kim, cholong Kim, Seong Hun Choi, J. Won, Taek Ahn, Yun Ho Kim","doi":"10.1088/2515-7639/ad1ea0","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1ea0","url":null,"abstract":"\u0000 We have prepared a low-temperature cross-linked soluble polyimide (SPI) as a dielectric material for organic thin-film transistors (OTFTs) to improve their electrical stability. Two types of soluble polyimides (DOCDA/6FHAB and 6FDA/6FHAB) were synthesized by a one-step polymerization process using 5-(2,5-dioxytetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA) and hexafluoroisopropylidene diphthalic anhydride (6FDA) as the dianhydrides and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FHAB) as a diamine. To further enhance the electrical performance, the SPI thin films were crosslinked with methylated/ethylated (hydroxymethyl)benzoguanamine (HMBG) through a low temperature process at 160 °C. Crosslinking considerably improved the insulating properties, resulting in a substantial reduction in leakage current from 10-7 A cm-2 to 10-9 A cm-2 at 2.0 MV cm-1. When crosslinked SPIs were used as gate dielectrics in OTFTs, device stability and reliability, as measured by the off-current, threshold voltage, and hysteresis, improved significantly. Our results demonstrate the potential of crosslinked SPIs as effective gate dielectric materials for advanced organic thin-film transistors.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139620899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electric field control of magnetization reversal in FeGa/PMN-PT thin films","authors":"Gajanan Pradhan, F. Celegato, Alessandro Magni, M. Coïsson, G. Barrera, P. Rizzi, P. Tiberto","doi":"10.1088/2515-7639/ad1e13","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1e13","url":null,"abstract":"\u0000 Artificial magnetoelectric materials possess huge potential to be utilized in the development of energy efficient spintronic devices. In the past decade, the search for a good ferromagnetic/ferroelectric combination having the ability to create high magnetoelectric coupling, created new insights and also new challenges. In this report, the magnetoelectric effect is studied in the FeGa/PMN-PT(001) multiferroic heterostructures in presence of electric fields via the strain-mediated effects. A formation of magnetic anisotropy in FeGa is observed after changing the polarization of PMN-PT to out-of-plane orientations. The magnetic domains structures forming during the magnetization reversal were studied at compressive, tensile and remanent strained states. The change in the magnetic properties were reversible after each cycling of the electric field polarity, hence creating a non-volatile system. The control of magnetization switching sustained by an ON-OFF electric field makes our multiferroic heterostructure suitable for application in low-power magnetoelectric based memory applications.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139625121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced doping and structure relaxation of unsubstituted polythiophene through oxidative chemical vapor deposition and mild plasma treatment","authors":"Yuxuan Zhang, Mingyuan Liu, Hyo-Young Yeom, Byung-Hyuk Jun, Jinwook Baek, Kwangsoo No, H. Song, Sunghwan Lee","doi":"10.1088/2515-7639/ad1c02","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1c02","url":null,"abstract":"\u0000 We report on the enhancement of electrical properties of unsubstituted polythiophene (PT) through oxidative chemical vapor deposition (oCVD) and mild plasma treatment. The work function of p-type oCVD PT increases after the treatment, indicating the Fermi level shift toward the valence band edge and an increase in carrier density. In addition, regardless of initial values, nearly the same work function is obtained for all the plasma-treated oCVD PT films as high as ~5.25 eV, suggesting the pseudo-equilibrium state is reached in the oCVD PT from the plasma treatment. This increase in carrier density after plasma treatment is attributed to the activation of initially not-activated dopant species (i.e., neutrally charged Br), which is analogous to the release of trapped charge carriers to the valence band of the oCVD PT. The enhancement of electrical properties of oCVD PT is directly related to the improvement of the thin film transistor performance such as drain current on/off ratio, ~103 and field effect mobility, 2.25 x 10-2 cm2/Vs, compared to untreated counterparts of 102 and 0.09 x 10-2 cm/Vs, respectively.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139446011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Impact of Metal Dopants on the Properties of nZVI: A Theoretical Study","authors":"J. White, J. Hinsch, William Bennett, Yun Wang","doi":"10.1088/2515-7639/ad1c03","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1c03","url":null,"abstract":"\u0000 The substitution of Fe with metal dopants shows potential for enhancing the wastewater remediation performance of nanoscale zero-valent iron (nZVI). However, the specific roles and impacts of these dopants remain unclear. To address this knowledge gap, we employed density functional theory (DFT) to investigate metal-doped nZVI on stepped surfaces. Four widely used metal dopants (Ag, Cu, Ni, and Pd) were investigated by replacing Fe atoms at the edge of the stepped surface. Previous research has indicated that these Fe atoms exhibit chemical reactivity and are vulnerable to water oxidation. Our DFT calculations revealed that the replacement of Fe atoms on the edge of the stepped surface is energetically more favorable than that on the flat Fe(110) surface. Our results shed light on the effects of metal dopants on the surface properties of nZVI. Notably, the replacement of Fe atoms with a metal dopant generally led to weaker molecular and dissociated water adsorption across all systems. The results from this study enhance our understanding of the complex interplay between dopants and the surface properties of nZVI, offering theoretical guidance for the development and optimization of metal-doped nZVI for efficient and sustainable wastewater remediation applications.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139446571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electronic transport properties of spin-crossover polymer plus polyaniline composites with Fe3O4 nanoparticles","authors":"Esha Mishra, Wai Kiat Chin, K. McElveen, T. K. Ekanayaka, Moahmmad Zaz, Gauthami Viswan, Ruthi Zielinski, A. N’Diaye, David Shapiro, Rebecca Y Lai, R. Streubel, P. A. Dowben","doi":"10.1088/2515-7639/ad1b35","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1b35","url":null,"abstract":"\u0000 Adding Fe3O4 nanoparticles to composites of [Fe(Htrz)2(trz)](BF4) spin-crossover polymer and polyaniline drives a phase separation of both and restores the molecular structure and cooperative effects of the spin-crossover polymer without compromising the increased conductivity gained through the addition of polyaniline. We observe an increased on-off ratio for the DC conductivity owing to an enlarged off state resistivity and a 20 times larger AC conductivity of the on state compared with DC values. The Fe3O4 nanoparticles, primarily confined to the [Fe(Htrz)2 (trz)](BF4 ) phase, are ferromagnetically coupled to the local moment of the spin-crossover molecule suggesting the existence of an exchange interaction between the both components.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139385009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applications of scanning probe microscopy in neuroscience research","authors":"D. McRae, Z. Leonenko","doi":"10.1088/2515-7639/ad1d89","DOIUrl":"https://doi.org/10.1088/2515-7639/ad1d89","url":null,"abstract":"\u0000 Scanning probe microscopy techniques allow for label-free high-resolution imaging of cells, tissues, and biomolecules in physiologically relevant conditions. These techniques include atomic force microscopy (AFM), atomic force spectroscopy, and Kelvin probe force microscopy, which enable high resolution imaging, nanomanipulation and measurement of the mechanoelastic properties of neuronal cells, as well as scanning ion conductance microscopy, which combines electrophysiology and imaging in living cells. The combination of scanning probe techniques with optical spectroscopy, such as with AFM-IR and tip-enhanced Raman spectroscopy, allows for the measurement of topographical maps along with chemical identity, enabled by spectroscopy. In this work, we review applications of these techniques to neuroscience research, where they have been used to study the morphology and mechanoelastic properties of neuronal cells and brain tissues, and to study changes in these as a result of chemical or physical stimuli. Cellular membrane models are widely used to investigate the interaction of the neuronal cell membrane with proteins associated with various neurological disorders, where scanning probe microscopy and associated techniques provide significant improvement in the understanding of these processes on a cellular and molecular level.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139634549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How to identify and characterize strongly correlated topological semimetals","authors":"Diana M Kirschbaum, Monika Lužnik, Gwenvredig Le Roy, Silke Paschen","doi":"10.1088/2515-7639/ad0f30","DOIUrl":"https://doi.org/10.1088/2515-7639/ad0f30","url":null,"abstract":"How strong correlations and topology interplay is a topic of great current interest. In this perspective paper, we focus on correlation-driven gapless phases. We take the time-reversal symmetric Weyl semimetal as an example because it is expected to have clear (albeit nonquantized) topological signatures in the Hall response and because the first strongly correlated representative, the noncentrosymmetric Weyl–Kondo semimetal Ce₃Bi₄Pd₃, has recently been discovered. We summarize its key characteristics and use them to construct a prototype Weyl–Kondo semimetal temperature-magnetic field phase diagram. This allows for a substantiated assessment of other Weyl–Kondo semimetal candidate materials. We also put forward scaling plots of the intrinsic Berry-curvature-induced Hall response vs the inverse Weyl velocity—a measure of correlation strength, and vs the inverse charge carrier concentration—a measure of the proximity of Weyl nodes to the Fermi level. They suggest that the topological Hall response is maximized by strong correlations and small carrier concentrations. We hope that our work will guide the search for new Weyl–Kondo semimetals and correlated topological semimetals in general, and also trigger new theoretical work.","PeriodicalId":501825,"journal":{"name":"Journal of Physics: Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138693335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}