Journal of physics. Condensed matter : an Institute of Physics journal最新文献

{"title":"First-principles study of influence of charged and neutral vacancy defects on mechanical and electronic properties of single layer CrI3.","authors":"Amrendra Kumar, Anjana E Sudheer, G Tejaswini, D Murali, C Kamal","doi":"10.1088/1361-648X/aea1d0","DOIUrl":"10.1088/1361-648X/aea1d0","url":null,"abstract":"<p><p>Intrinsically magnetic two-dimensional (2D) materials provide an ideal platform for exploring magnetism in reduced dimensions and have attracted significant attention due to their potential applications in next-generation spintronic devices. The performance of such devices strongly depends on the structural quality and defect morphology of the underlying 2D materials. Point defects play a crucial role, acting either as beneficial tools for property engineering or as detrimental factors leading to device degradation. Recently, atomic iodine vacancies (), atomic chromium vacancies (), and vacancy complexes () have been experimentally identified. Motivated by experimental findings, we investigate the influence of vacancy defects on the structural, mechanical, electronic, and magnetic properties of single-layer CrIin the present work. Although several theoretical studies have reported the electronic and magnetic properties of CrIsingle layer with vacancy defects, a systematic investigation of influence of vacancies on mechanical properties remains largely unexplored. Our calculations show that the presence of vacancies significantly degrades the elastic properties. For a defect concentration of 1.39%, the Young's modulus decreases to 20.88 and 16.66 N mforand, respectively. For vacancy complexes with concentrations of 5.56% () and 9.72% (), the Young's modulus further reduces to 18.28 and 16.20 N m, respectively, compared to 24.12 N mfor the pristine system. This reduction indicates a softening of the single-layer CrIdue to vacancies. Furthermore, we find that the mechanical properties of charged and neutral defects do not differ significantly and are primarily governed by structural distortions. On the other hand, vacancy defects alter the electronic character, either transforming the system from semiconducting to half-metallic or leading to a reduction in the band gap. Importantly, the magnetic properties remain robust in the presence of vacancy defects. Overall, the present study provides insights into influence of vacancy defects on the mechanical and electronic properties of single layer CrI, thereby improving our understanding of defect engineering in 2D magnetic materials.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883394","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 energy levels in quantum dots with weakly modulated spherical-harmonic surfaces.","authors":"Roman Leshko, Olha Leshko, Taras Monastyrskyi","doi":"10.1088/1361-648X/aea680","DOIUrl":"10.1088/1361-648X/aea680","url":null,"abstract":"<p><p>The precise control of quantum dot (QD) geometry is crucial for tailoring their optoelectronic properties, yet an exact analytical description of non-spherical nanoparticles remains mathematically challenging. In this work, we present a comprehensive theoretical framework to calculate the electronic energy spectra of QDs with arbitrary weakly modulated spherical-harmonic surfaces. Utilizing the perturbation theory up to the second order, we derive analytical expressions for the energy corrections. The important feature of our approach is the explicit incorporation of Wigner 3j-symbols, which establishes selection rules based on the spatial and axial symmetries of the surface corrugations. The model is validated through numerical calculations for a GaAs QD under various geometric configurations, including spheroidal, pear-shaped, and multi-harmonic shapes. The proposed analytical tool offers deep physical insights into the quantum confinement effect in realistically corrugated nanocrystals, providing a computationally efficient platform for the shape-engineering of semiconductor nanomaterials.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148946493","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":"Quantum optimization algorithms for strongly correlated many-body systems.","authors":"G E L Pexe, L A M Rattighieri, P M Prado, A R Fritsch, F F Fanchini","doi":"10.1088/1361-648X/ae9dd5","DOIUrl":"10.1088/1361-648X/ae9dd5","url":null,"abstract":"<p><p>This perspective assesses quantum algorithms for phase transitions and low-energy properties of strongly correlated many-body systems in the noisy intermediate-scale quantum era. We compare the variational quantum eigensolver (VQE), the quantum approximate optimization algorithm (QAOA), feedback-based protocols such as Feedback-based ALgorithm for Quantum OptimizatioN (FALQON), adaptive variational methods, and quantum-subspace approaches. The comparison separates circuit depth, classical processing, and measurement overhead because no single metric establishes uniform superiority. We discuss symmetry-preserving and particle-number-conserving circuits, tensor-network-assisted initialization, variational imaginary-time evolution, Sample-based Krylov quantum diagonalization, and basis-adaptive algorithms. These methods are connected to deconfined quantum criticality, strange metals, many-body localization, topological transitions, and quantum spin liquids, with order-of-magnitude resource windows and measurement bottlenecks stated explicitly. Feedback-guided methods remove a high-dimensional external optimizer and can preserve selected symmetries, but exchange these advantages for layer-by-layer commutator measurements, progressive circuit growth, and sensitivity to noise. The available evidence therefore supports a problem-dependent portfolio of physics-informed, symmetry-aware, and classically assisted algorithms rather than a universal ranking among VQE, QAOA, and FALQON.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148815241","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":"High-harmonic generation in topological materials: a comprehensive review.","authors":"Muhammad Subhan Riaz, Hongxiang Deng, Xia Xiang, Xiaotao Zu, Sean Li","doi":"10.1088/1361-648X/aea1b4","DOIUrl":"10.1088/1361-648X/aea1b4","url":null,"abstract":"<p><p>In solids, high-harmonic generation (HHG) has emerged as a crucial technique for studying ultrafast electron dynamics and band structure properties. Topological quantum materials, including topological insulators (TIs), semimetals and topological superconductors are an emerging class of materials distinguished by their unique edge or surface states along with nontrivial Berry curvature and topological invariants. These fundamental properties impart distinctive signatures onto their high-harmonic spectra, offering a novel nonlinear-optical window into topological order. Several theoretical and experimental investigations have shown that HHG in topological materials exhibits distinct signatures, including significant circular dichroism, enhanced harmonic yields, and distinctive ellipticity dependence, highlighting its sensitivity to underlying topological properties. This article aims to describe the basic dynamics that drive HHG in these materials, point out important theoretical and experimental results, and evaluate which spectral features may be genuinely topology-specific, which are topology-sensitive but not unique, and which remain debated. We organized the review into three main sections covering TIs, semimetals, and superconductors. For each class, after providing a basic overview, we explore the distinctive HHG mechanisms and spectral characteristics.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148881976","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":"Superconductivity in bilayer La$_3$Ni$_2$O$_7$ : A review focusing on the strong-coupling Hund's rule assisted pairing mechanism.","authors":"Zhiming Pan, Chen Lu, Fan Yang, Congjun Wu","doi":"10.1088/1361-648X/aea8b1","DOIUrl":"https://doi.org/10.1088/1361-648X/aea8b1","url":null,"abstract":"<p><p>The discoveries of high-$T_c$ superconductivity (SC) in bulk bilayer La$_3$Ni$_2$O$_7$ under pressure and of ambient-pressure SC in compressively strained thin films provide an important platform for exploring unconventional SC. Experiments reveal orbital-dependent band renormalization and sizable interlayer magnetic correlations, and show that SC emerges in association with pressure- or strain-induced structural changes. However, the role of the $gamma$ band, the symmetyr of the superconducting gap, and the microscopic pairing mechanism remain unresolved. This article reviews the relevant experimental observations and theoretical developments, with a focus on the strong-coupling Hund-assisted interlayer-pairing scenario. Within this framework, the two active Ni $E_g$ orbitals play distinct roles. In the local strong-coupling limit, the nearly half-filled and heavily renormalized $3d_{z^2}$ orbitals experience a sizable antiferromagnetic exchange across the bilayer through the inner apical oxygen. This exchange is proposed to favor interlayer rung-singlet correlations and may produce an orbital-dependent pseudogap regime. The onsite Hund's coupling aligns the two $E_g$ spins and generates an effective interlayer exchange between the more itinerant $3d_{x^2-y^2}$ carriers. The resulting bilayer models favor an interlayer $s$-wave state and predict that electron doping strengthens pairing.&#xD;The Hund-assisted scenario can accommodate either the presence or absence of a $gamma$ pocket, provided that the $3d_{z^2}$ sector retains substantial local-moment character and sizable interlayer spin correlations. We also compare this framework with weak- and intermediate-coupling theories and other strong-coupling proposals.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148983844","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":"Ground-state properties of uniaxial magnetic model for antiferromagnetic 1/1 periodic approximants to icosahedral quasicrystals.","authors":"Shinji Watanabe","doi":"10.1088/1361-648X/ae95cc","DOIUrl":"10.1088/1361-648X/ae95cc","url":null,"abstract":"<p><p>The ground-state properties of the uniaxial magnetic model in the 1/1 periodic approximant to the icosahedral quasicrystal with antiferromagnetic interactions for the nearest-neighbor bondand the next-nearest-neighbor bondare analyzed theoretically. By performing numerically-exact calculation, we have determined the ground-state phase diagram for the interaction strengthand the magnetic anisotropy defined within the mirror plane reflecting the effect of the crystalline electric field. We have discovered non-collinear magnetic structures, whose magnetic space groups are identified as the antiferromagnetic ordersandwith the magnetic propagation vectoras well as the antiferromagnetic orders,andwith the magnetic propagation vectorand the ferrimagnetic orders,,, and. By analyzing each ground state with degeneracy, we have revealed the magnetic as well as topological properties, which are useful to analyze experimental observations of rare-earth-based 1/1 approximants considering the effect of magnetic domains.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148682003","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":"Spin-orbit-enhanced correlation sensitivity and anomalous magnetic response in non-dimerized 4d⁴ilmenite CdRuO₃.","authors":"Yuya Haraguchi, Hayato Yatsuzuka, Hiroko Aruga Katori","doi":"10.1088/1361-648X/aea2fd","DOIUrl":"10.1088/1361-648X/aea2fd","url":null,"abstract":"<p><p>We report the synthesis and physical properties of CdRuO₃, a nominal Ru⁴⁺4d⁴ilmenite with edge-sharing RuO₆honeycomb layers. Powder x-ray diffraction establishes a crystallographically non-dimerizedstructure with equivalent Ru-Ru bonds and a strongly distorted RuO₆environment. The compacted-pellet resistivity is nonmetallic but non-Arrhenius, while the heat capacity contains a finite residual linear term. Matched nonmagnetic calculations show that PBE +<i>U</i>without spin-orbit coupling remains metallic or semimetallic up to<i>U</i>_eff= 3 eV, whereas PBE + SOC +<i>U</i>exhibits a strong<i>U</i>_effdependence and opens a direct gap of approximately 55 meV at Γ for<i>U</i>_eff= 2.5 eV. Spin-orbit coupling therefore markedly enhances the correlation sensitivity of the non-cubic Ru<i>t</i>_2gmanifold. After subtraction of a dilute Curie-Weiss defect contribution, the susceptibility remains weakly nonmonotonic and is inconsistent with both an ordinary Pauli response and independent spin-only<i>S</i>= 1 moments. CdRuO₃thus realizes the non-dimerized structural branch predicted for ruthenium ilmenites, but not a simple robust multiorbital metal.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148893365","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":"Computational dissection of single-layer intrinsic ferromagnetic semiconductor Mn₂AX₆(A=Al, Ga; X=Cl, Br, I) with large magnetic anisotropy and high Curie temperature.","authors":"Hengtao Li, Jing Zou, Yong Li, Jingtao Li, Zeyu Jiang, Liujiang Zhou","doi":"10.1088/1361-648X/ae9f07","DOIUrl":"10.1088/1361-648X/ae9f07","url":null,"abstract":"<p><p>Two-dimensional intrinsic ferromagnetic semiconductors (IFMS) have emerged as a pivotal research frontier in spintronics, uniquely enabling integration of semiconductor electronics with non-volatile magnetic storage at finite temperatures. Using first-principles calculations, we systematically investigated the structural stability, electronic, and magnetic properties of potential Mn₂AX₆(A=Al, Ga; X=Cl, Br, I) materials with large-moment IFMS characteristics. Results confirm that these stable materials are indeed IFMS with an indirect bandgap ranging from 0.5 to 1.3 eV and a magnetization of 9<i>μ</i>B u.c.^-1And their IFMS characteristics show exceptional resilience to strain. The semiconducting property transition to half-metal characteristic only when compressive strain exceeds 7% (as seen in Mn₂AlCl₆), while spin-polarized band inversion occurs when the strain shifts from compressive to tensile. Additionally, these monolayers consistently exhibit out-of-plane easy magnetization axes with magnetic anisotropy energy of 0.028-2.1 meV and Curie temperatures (<i>T</i>_c) of 164<b>-</b>303 K. Further studies on magnetic mechanism reveal that their ferromagnetic ground states are predominantly governed by<b><i>d_xy</i>-<i>p_xy</i>-<i>d_xy</i></b>superexchange interactions within Mn<b>-</b>X<b>-</b>Mn pathways near ∼90°, with the concomitant high-<i>T</i>_cbeing attributable to the larger magnetic moments (∼4.6<i>μ</i>_B) of Mn²⁺and strong second- and third-nearest- neighbor Mn-Mn magnetic interactions compared to other transition metal (TM) dihalides. Collectively, these IFMS materials Mn₂AX₆, with advantages including strain-tunable spin flip and balanced magnetic properties, may exhibit greater potential than other TM halides for magnetic storage and magnetic sensor applications.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148835726","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":"Orienting-field effects on instability and mode selection in active nematics.","authors":"I K Joseph, A J H Houston, K N Kowal, N J Mottram","doi":"10.1088/1361-648X/aea1cf","DOIUrl":"10.1088/1361-648X/aea1cf","url":null,"abstract":"<p><p>We examine the instabilities of a confined active nematic subjected to an orienting field using a low Reynolds number Ericksen-Leslie framework with active stresses and field-induced torques. Linear analysis reveals two distinct modes, with odd and even director symmetry, the instabilities of which depend on the interplay between activity and field strength. We derive exact and approximate analytic forms of the stability boundaries and show that an orienting field that aligns the director perpendicular to the substrate anchoring direction cooperatively lowers activity thresholds and enables a field-driven even symmetry mode instability, while an orienting field that aligns the director parallel to the substrate anchoring tends to stabilise the system. Numerical solutions of the full nonlinear equations show that the linear stability analysis correctly identifies the symmetries of long-time states. These results demonstrate how orienting fields can promote an instability below the classical critical activity and can be used to both tune the instability onset and control the mode selection in confined active nematics.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883170","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":"Ultrafast charge and energy transfer dynamics in solids and at interfaces revealed by time-resolved x-ray absorption spectroscopy.","authors":"A Eschenlohr","doi":"10.1088/1361-648X/aea1b5","DOIUrl":"10.1088/1361-648X/aea1b5","url":null,"abstract":"<p><p>The excitation of solid materials with femtosecond optical pulses induces non-equilibrium states that are interesting for both fundamental and application-related reasons, as their properties can be quite different from those generated by e.g. thermal excitation or chemical doping. However, once several degrees of freedom such as electronic and lattice excitations, or multiple components in a heterostructure, couple strongly, analyzing the resulting ultrafast dynamics on femto- to picoseconds requires element-sensitive spectroscopy on these timescales. This Topical Review discusses how new insights into ultrafast charge and energy transfer dynamics in solids and at interfaces can be gained from time-resolved soft x-ray absorption spectroscopy (XAS). The state-of-the-art of the pump-probe XAS method at large scale facilities, namely synchrotron Femtoslicing sources and x-ray free electron lasers, is reviewed, with an emphasis on the opportunities and challenges of the respective facilities that motivate new methodological developments. For three selected material systems, it is then shown how XAS with femtosecond time resolution, in conjunction with theoretical calculations, is able to reveal and characterize non-equilibrium states by analyzing the transient electronic structure as well as lattice excitation via characteristic, time-dependent spectral features. Finally, future opportunities through the further development of laboratory-based soft x-ray sources and the combination of time-resolution with non-linear XAS are presented.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883291","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}