Journal of Physics: Condensed Matter最新文献

{"title":"Stacking ferroelectricity in two-dimensional van der Waals materials.","authors":"Zhigang Gui, Li Huang","doi":"10.1088/1361-648X/ada65a","DOIUrl":"https://doi.org/10.1088/1361-648X/ada65a","url":null,"abstract":"<p><p>Miniaturization of ferroelectrics for technological applications has proven challenging due to the suppression of electric polarization caused by increasing depolarization fields as material thickness decreases. The emergence of ferroelectricity in two-dimensional (2D) van der Waals (vdW) materials offers a potential solution to this challenge, prompting significant research efforts over the past decade. While intrinsic 2D vdW ferroelectrics are scarce, polar stacking provides a more general approach to introducing ferroelectricity in these materials. This review revisits the fundamental concept of stacking ferroelectricity, complemented by symmetry analysis for constructing polar stackings, and both classical and quantum perspectives on the origin of stacking ferroelectrics. We present key advances in polarization dynamics and briefly summarize various physical phenomena directly coupled to stacking ferroelectricity, including multiferroic, magnetoelectric, and valleytronic effects, along with their related applications. Finally, we discuss future challenges and potential developments in the field of 2D stacking ferroelectricity.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical origin and control of exciton spatial localization in high-<i>κ</i>MOene monolayers under external perturbations.","authors":"Amal Kishore, Harshita Seksaria, Abir De Sarkar","doi":"10.1088/1361-648X/ada65f","DOIUrl":"https://doi.org/10.1088/1361-648X/ada65f","url":null,"abstract":"<p><p>Two-dimensional (2D) materials hold great promise for the next-generation optoelectronics applications, many of which, including solar cell, rely on the efficient dissociation of exciton into free charge carriers. However, photoexcitation in atomically thin 2D semiconductors typically produces exciton with a binding energy of ∼500 meV, an order of magnitude larger than thermal energy at room temperature. This inefficient exciton dissociation can limit the efficiency of photovoltaics. In this study, employing the first principles approach-DFT, GW + BSE, and analytical model, we demonstrate the role of asymmetric halogenation, dielectric environment, and magnetic field in 2D Ti₂O MOene as an efficient strategy for regulating exciton binding energy (EBE) towards spontaneous exciton dissociation. Our study goes beyond the exciton ground state and quantifies the degree of spatial delocalization of exciton in excited states as well. We determine the quantitative impact of varying dielectric screening and magnetic field strength on EBE for different excited states (1 s, 2 s, 3 s, 4 s, and so on). Importantly, we reveal the significant role of orbital orientation (whether in-plane or out-of-plane) and symmetry (related to the angular momentum quantum number) in understanding the spatial localization of excitons and their binding energy. Additionally, a high dielectric constant in 2D MOene enables easier exciton dissociation, similar to that observed in 3D bulk semiconductors, while also harnessing the advantages of 2D materials. This makes it an effective material that combines the best of both 3D bulk and 2D structures. The study offers a promising strategy for designing next-generation optoelectronic devices.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational condensed matter science contributions to addressing water emerging contaminant pollution: a comprehensive review.","authors":"José Rafael Bordin, Carolina Ferreira de Matos Jauris, Patrick R B Côrtes, Wanderson S Araújo, Luana S Moreira, Alexsandra Pereira Dos Santos, Mayara Bitencourt Leão, Elizane E Moraes, Maurício J Piotrowski, Mateus H Köhler","doi":"10.1088/1361-648X/ada65b","DOIUrl":"https://doi.org/10.1088/1361-648X/ada65b","url":null,"abstract":"<p><p>The study of emerging contaminants (ECs) in water resources has garnered significant attention due to their potential risks to human health and the environment. This review examines the contribution from computational approaches, focusing on the application of machine learning (ML) and molecular dynamics (MD) simulations to understand and optimize experimental applications of ECs adsorption on carbon-based nanomaterials. Condensed matter physics plays a crucial role in this research by investigating the fundamental properties of materials at the atomic and molecular levels, enabling the design and engineering of materials optimized for contaminant removal. We provide a comprehensive discussion of various force fields (FFs) such as AMBER, CHARMM, OPLS, GROMOS, and COMPASS, highlighting their unique features, advantages, and specific applications in modeling molecular interactions. The review also delves into the development and application of reactive potentials like ReaxFF, which facilitate large-scale atomistic simulations of chemical reactions. Additionally, we explore how ML models, including sGDML and SchNet, significantly enhance the potential and refinement of classical models by providing high-level quantum descriptions at reduced computational costs. The integration of ML with MD simulations allows for the accurate parameterization of FFs, offering detailed insights into adsorption mechanisms. Through a qualitative analysis of various ML models applied to the study of ECs on carbon materials, we identify key physical and chemical descriptors influencing adsorption capacities. Despite these advancements, challenges such as the limited diversity of ECs studied and the need for extensive experimental validation persist. This review underscores the importance of interdisciplinary collaboration, particularly the contributions of condensed matter physics, in developing innovative materials and strategies to address the environmental challenges posed by ECs.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybridization effects on the magnetic ground state of ruthenium in double perovskite La₂ZnRu_1-<i>x</i>Ti_<i>x</i>O₆.","authors":"Shuvajit Halder, Carlo Meneghini, Sugata Ray","doi":"10.1088/1361-648X/ada679","DOIUrl":"https://doi.org/10.1088/1361-648X/ada679","url":null,"abstract":"<p><p>An exotic quantum mechanical ground state, i.e. the non-magnetic<i>J</i>_eff= 0 state, has been predicted for higher transition metalt2g4systems, due to the influence of strong spin-orbit coupling (SOC) or in other words, due to unquenched orbital moment contribution. However, previous attempts to experimentally realize such a state in 5<i>d</i>⁴systems had mostly been clouded by solid-state effects or the reduced strength of the renormalized SOC that might allow significant triplon condensation. Interestingly, a recent study on vacancy ordered double perovskite compound K₂RuCl₆by Takahashi<i>et al</i>(2021<i>Phys. Rev. Lett.</i><b>127</b>227201) concluded that even within<i>LS</i>coupling regime the Ru⁴⁺4<i>d</i>⁴ions, within isolated RuCl₆octahedra, strongly accommodate<i>J</i>multiplets having<i>J</i>_eff= 0 as the ground state with weakly interacting<i>J</i>_eff= 1 excitation, due to large unquenced Ru orbital angular momentum in the system. In the present report, we show results from the double perovskite La₂ZnRuO₆, where Ru⁴⁺ions form isolated RuO₆octahedra but unlike K₂RuCl₆, they remain chemically connected via corner-sharing with nonmagnetic ZnO₆octahedra. Next, we move on to separate out the RuO₆octahedra further by doping the Ru-site with Ti⁴⁺, in order to probe the character of the Ru⁴⁺ions within a different structural background. We find that the system stabilizes in<i>P</i>21/nspace group with tilted octahedra without distortion as has been confirmed by the x-ray powder diffraction and x-ray absorption spectroscopic studies. Interestingly, the x-ray photoelectron spectroscopic valance band spectra indicated certain inhomogeneity around the half-doping region, while confirming insulating ground state for all. Moreover, unlike the vacancy ordered double perovskite cases, it is observed that here the Ru orbital angular momentum gets substantially quenched and only the Ru spin magnetic moments are realized.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, dielectric and magnetic properties of Sb/Cr-doped CaCu₃Ti₄O₁₂quadruple perovskite oxides.","authors":"Jie Ding, Xinhua Zhu","doi":"10.1088/1361-648X/ada50b","DOIUrl":"10.1088/1361-648X/ada50b","url":null,"abstract":"<p><p>Driven by the miniaturization of microelectronic devices and their multifunctionalities, the development of new quadruple-perovskite oxides with high dielectric constants and high Curie temperature are highly required. Herein, we report on the structural, dielectric and magnetic properties of Sb/Cr-doped CaCu₃Ti₄O₁₂(CCTO) quadruple perovskite oxides, CaCu₃Ti_3.9Sb_0.1O₁₂(CCTSO) and CaCu₃Ti₃CrO₁₂(CCTCO). Structural Rietveld refinements demonstrated that the CCTO, CCTSO, and CCTCO ceramics adopted a cubic crystal structure (<i>Im</i>3¯ space group). They exhibited spherical shapes with nearly uniform particle sizes. XPS spectra clarified Cu³⁺ions in the CCTSO ceramics, while Cu²⁺and Cu⁺ions, and Cr³⁺ions in the CCTCO ceramics. All the ceramic samples displayed nearly frequency independent dielectric behaviors at low temperatures but a relaxor dielectric behavior at high temperatures. Such relaxor dielectric behavior in the CCTO and CCTSO ceramics was ascribed to the movement of doubly ionized oxygen vacancies but in the CCTCO ceramics to the movement of singly ionized oxygen vacancies. Impedance and modulus spectra reveal the significance contributions of grains and grain boundaries with non-Debye behavior. At room temperature (RT) the dielectric constant (<i>ϵ</i>_r) and dielectric loss (tan<i>δ</i>) of CCTO ceramics at 1 kHz were 15 922 and 0.126, respectively. An order reduction of tan<i>δ</i>was achieved in the CCTSO ceramics. In the CCTCO ceramics, the<i>ϵ</i>_rand tan<i>δ</i>at RT and 1 kHz were 975 and 0.453, respectively. The CCTCO powders exhibited antiferroelectric behavior at 2 K with a saturation magnetization (<i>M</i>_S) of 1.42<i>μ</i>_B/f.u., while the<i>M</i>_Sfor the CCTSO powders was only 0.027<i>μ</i>_B/f.u. All ceramic samples exhibited semiconductor characteristics owing to their continuous decreases of resistivity from 2 K to 800 K. Our present work demonstrates an effective route to tuning the dielectric and magnetic properties of CCTO oxides via B-site non-magnetic/magnetic ion-doping.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142921749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diffusion, mechanical and thermal properties of sT hydrogen hydrate by machine learning potential.","authors":"Zixuan Song, Yuan Li, Qiao Shi, Yongxiao Qu, Yongchao Hao, Rui Ma, Zhisen Zhang, Jianyang Wu","doi":"10.1088/1361-648X/ada710","DOIUrl":"10.1088/1361-648X/ada710","url":null,"abstract":"<p><p>Newly-synthesized structure T (sT) hydrate show promising practical applications in hydrogen storage and transport, yet the properties remain poorly understood. Here, we develop a machine learning potential (MLP) of sT hydrogen hydrate derived from quantum-mechanical molecular dynamics simulations. Using this MLP forcefield, the structural, hydrogen diffusion, mechanical and thermal properties of sT hydrogen hydrate are extensively explored. It is revealed that the translational and rotational mobilities of hydrogen molecule in sT hydrate are limited due to unique shape and finite dimensional cavities, and tiny windows of neighboring cavities. sT hydrogen hydrate exhibits unique uniaxial tension stress-strain response, with first nonlinear increase to GPa-level but followed by deep drop in the stretching stress, indicating brittle failure, similar to that by Density Functional Theory and empirical forcefields. Moreover, temperature-dependent thermal conductivity in sT hydrogen hydrate is mainly contributed by hydrogen-bonded network formed by host water molecules, while hydrogen guest molecules play an insignificant role in the thermal transport.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the correlation between chemical bonding and structural distortions in TbCu_0.33Te₂.","authors":"Leander Weinelt, Simon Steinberg","doi":"10.1088/1361-648X/ada411","DOIUrl":"https://doi.org/10.1088/1361-648X/ada411","url":null,"abstract":"<p><p>The design of solid-state materials requests a thorough understanding of the structural preferences among plausible structure models. Since the bond energy contributes to the formation energy of a given structure model, it also is decisive to determine the nature of chemical bonding for a given material. In this context, we were motivated to explore the correlation between chemical bonding and structural distortions within the low-dimensional tellurium fragments in TbCu_0.33Te₂. The ternary telluride was obtained from high-temperature solid-state reactions, while structure determinations based on x-ray diffraction experiments did not point to the presence of any structural distortion above 100 K. However, the results of first-principles-based computations indicate that a potential structural distortion within the low-dimensional tellurium fragments also correlates to an optimization of overall bonding.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reinvestigating atomic ordering inK0.5Na0.5NbO3and its impact on ferroelectric properties.","authors":"Anuvrat Tripathi, Saurabh Tripathi","doi":"10.1088/1361-648X/ada65d","DOIUrl":"https://doi.org/10.1088/1361-648X/ada65d","url":null,"abstract":"<p><p>In the present work, we reinvestigate the atomic ordering of a Pb-free morphotropic phase boundary (MPB) compositionviz.,K0.5Na0.5NbO3(KNN50) and its vicinity at various length scales using high-resolution x-ray diffraction and pair distribution function data. We have observed a monoclinic phase (Space Group: Pm) at long/short ranges differing from a very recent report by Saha<i>et al</i>2024<i>J. Phys.: Condens. Matter</i><b>36</b>425703. Moreover, the ferroelectric (polarization) dominance of short-range ordering (SRO) over long-range ordering (LRO) has been observed and quantified for the very first time using the amplitude of the ferroelectric frozen phonon mode (Γ4-) (corresponding to the high symmetry cubic phase), thereby structure is linked with ferroelectric (or polarization) property for a widely studied MPB systemviz.,KxNa(1-x)NbO3(KNN<i>x</i>for<i>x</i>= 0.40, 0.50, and 0.60). Two uniquely identified monoclinic phases has been observed for SRO (MSRO) and LRO (MLRO) for all the compositions. The amplitude of ferroelectric frozen phonon mode (Γ4-) corresponding toMSROis significantly higher (≈150%-180%) thanMLRO. A peak is observed in the amplitude ofΓ4-and intensity of prominent Raman peaks (<i>ν</i>₁and<i>ν</i>₅) for<i>x</i>= 0.50, which is held responsible for high physical propertiesviz.,dielectric permittivity, piezoelectric coefficient, remnant polarization, electromechanical coupling coefficient, and many more widely reported in literature for KNN50.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral heat flux redistribution upon interfacial transmission.","authors":"Haoran Cui, Theodore Maranets, Tengfei Ma, Yan Wang","doi":"10.1088/1361-648X/ada660","DOIUrl":"https://doi.org/10.1088/1361-648X/ada660","url":null,"abstract":"<p><p>In nonmetallic crystals, heat is transported by phonons of different frequencies, each contributing differently to the overall heat flux spectrum. In this study, we demonstrate a significant redistribution of heat flux among phonon frequencies when phonons transmit across the interface between dissimilar solids. This redistribution arises from the natural tendency of phononic heat to re-establish the bulk distribution characteristic of the material through which it propagates. Remarkably, while the heat flux spectra of dissimilar solids are typically distinct in their bulk forms, they can become nearly identical in superlattices or sandwich structures where the layer thicknesses are smaller than the phonon mean free paths. This phenomenon reflects that the redistribution of heat among phonon frequencies to the bulk distribution does not occur instantaneously at the interface, rather it develops over a distance on the order of phonon mean-free-paths.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collective modes in terahertz field response of disordered superconductors.","authors":"Yantao Li, Maxim Dzero","doi":"10.1088/1361-648X/ada65e","DOIUrl":"https://doi.org/10.1088/1361-648X/ada65e","url":null,"abstract":"<p><p>We consider a problem of nonlinear response to an external electromagnetic radiation in conventional disordered superconductors which contain a small amount of weak magnetic impurities. We focus on the diffusive limit and use Usadel equation to analyze the excitation energy and dispersion relation of the collective modes. We determine the resonant frequency and dispersion of both amplitude (Schmidt-Higgs) and phase (Carlson-Goldman) modes for moderate strength of magnetic scattering. We find that the minimum energy required for the excitation of the both of these modes decreases with an increase in spin-flip scattering. Surprisingly we also find that as a result the Carlson-Goldman mode becomes gapless and as a consequence can only be excited at some finite value of the threshold momentum. We thus discover yet another physical realization of a state with gapped momentum dispersion of one of its collective modes. The value of the threshold momentum is determined by the distance between the two consecutive spin-flip scattering events which, in turn, is proportional to the scattering time between two consecutive scattering events. The amplitude mode is diffusive and becomes strongly suppressed with the increase in spin-flip scattering. Possible ways to experimentally verify our results are also discussed.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":"37 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}