npj Quantum Materials最新文献_第6页

Phases of quasi-one-dimensional fractional quantum anomalous Hall -- superconductor heterostructures 准一维分数量子反常霍尔超导体异质结构的相

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-05-28 DOI: 10.1038/s41535-026-00897-1

Steffen Bollmann, Andreas Haller, Jukka I. Väyrynen, Thomas L. Schmidt, Elio J. König

{"title":"Phases of quasi-one-dimensional fractional quantum anomalous Hall -- superconductor heterostructures","authors":"Steffen Bollmann, Andreas Haller, Jukka I. Väyrynen, Thomas L. Schmidt, Elio J. König","doi":"10.1038/s41535-026-00897-1","DOIUrl":"https://doi.org/10.1038/s41535-026-00897-1","url":null,"abstract":"Motivated by recent observations of fractional Chern insulators (FCIs) in the vicinity of superconducting (SC) phases, we study fractional quantum (anomalous) Hall-superconductor heterostructures in the presence of U(1) order-parameter fluctuations and particularly focus on the case of ν = 2/3 quantum Hall states leading to {{mathbb{Z}}}_{3}{{mathbb{Z}}}_{3} parafermions. We first employ a phenomenological field theory to qualitatively determine the phase diagram. Furthermore, we generalize a previously established alternating pattern of superconductor and tunneling regions, coupled to fractional quantum Hall edge states, to map the problem onto a topological Josephson junction chain involving lattice parafermions. Using density matrix renormalization group simulations, we establish a phase diagram composed of Mott insulating phases and two different Luttinger liquids whose fundamental excitations carry charges 2e and 2e/3, respectively. In agreement with analytical considerations using conformal field theory, we numerically find transitions of Berezinskii–Kosterlitz–Thouless (BKT) type as well as a continuous {{mathbb{Z}}}_{3}times U(1){{mathbb{Z}}}_{3}times U(1) second-order phase transition characterized by central charge c = 9/5. We finally extract information about a possible ground state degeneracy and comment on the stability of parafermionic edge states in the presence of fluctuations. These theoretical foundations can be expected to be of practical importance for gate-defined FCI-SC heterostructures in moiré materials, in which broad superconducting transitions indicative of strong order parameter fluctuations were observed.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"270 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148287208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

引用次数: 0

Impact of nonlocal Coulomb repulsion on superconductivity and density-wave orders in bilayer nickelates 非局域库仑斥力对双层镍酸盐超导性和密度波阶数的影响

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-05-27 DOI: 10.1038/s41535-026-00883-7

Jun Zhan, Congcong Le, Xianxin Wu, Jiangping Hu

{"title":"Impact of nonlocal Coulomb repulsion on superconductivity and density-wave orders in bilayer nickelates","authors":"Jun Zhan, Congcong Le, Xianxin Wu, Jiangping Hu","doi":"10.1038/s41535-026-00883-7","DOIUrl":"https://doi.org/10.1038/s41535-026-00883-7","url":null,"abstract":"The recent discovery of high-temperature superconductivity in pressurized bilayer nickelate La3Ni2O7 and its thin films has sparked considerable interest in unraveling their pairing mechanisms and correlated electronic states. While earlier theoretical studies have primarily focused on onsite Coulomb interactions, the impact of nonlocal Coulomb repulsion has remained largely unexplored. In this work, we systematically investigate the influence of nonlocal Coulomb interactions on both superconductivity and density-wave instabilities, in the presence of onsite interactions, by employing the functional renormalization group (FRG) approach. We find that the interlayer intra-orbital repulsion suppresses the interlayer intra-orbital s±-wave pairing and spin-density-wave (SDW) order, while promoting a transition to an interlayer inter-orbital ({d}_{{x}^{2}-{y}^{2}})-wave pairing state and a mirror-symmetry-breaking charge order. Remarkably, the critical scale of the inter-orbital ({d}_{{x}^{2}-{y}^{2}})-wave superconductivity is significantly lower than that of the intra-orbital s±-wave superconductivity, suggesting that the former pairing is unlikely to account for the observed high-Tc superconductivity. In addition, the interlayer inter-orbital repulsion suppresses this ({d}_{{x}^{2}-{y}^{2}})-wave pairing but promotes the s±-wave pairing owing to enhanced interlayer charge fluctuations. In addition, the intralayer nearest-neighbor repulsion favors an in-plane charge density wave (CDW) order with wave vector (π, π). Our findings highlight the profound impact of nonlocal Coulomb repulsion and the robustness of interlayer pairing associated with the bilayer structure and the multi-orbital nature, advancing the understanding of the complex correlation effects within bilayer nickelates.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"24 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148286918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

引用次数: 0

Z2{{mathbb{Z}}}_{2} vortex crystal candidate in the triangular S = 1/2 quantum antiferromagnet 三角形S = 1/2量子反铁磁体中Z2{{mathbb{Z}}}_{2}涡旋候选晶体

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-05-26 DOI: 10.1038/s41535-026-00894-4

Jakob Nagl, Kirill Yu. Povarov, Benjamin Duncan, Catharina Näppi, Dmitry Khalyavin, Pascal Manuel, Fabio Orlandi, Jeremy Sourd, Beat Valentin Schwarze, Freya Husstedt, Sergei A. Zvyagin, Oksana Zaharko, Paul Steffens, Arno Hiess, David R. Allan, Sarah A. Barnett, Zewu Yan, Severian Gvasaliya, Andrey Zheludev

{"title":"Z2{{mathbb{Z}}}_{2} vortex crystal candidate in the triangular S = 1/2 quantum antiferromagnet","authors":"Jakob Nagl, Kirill Yu. Povarov, Benjamin Duncan, Catharina Näppi, Dmitry Khalyavin, Pascal Manuel, Fabio Orlandi, Jeremy Sourd, Beat Valentin Schwarze, Freya Husstedt, Sergei A. Zvyagin, Oksana Zaharko, Paul Steffens, Arno Hiess, David R. Allan, Sarah A. Barnett, Zewu Yan, Severian Gvasaliya, Andrey Zheludev","doi":"10.1038/s41535-026-00894-4","DOIUrl":"https://doi.org/10.1038/s41535-026-00894-4","url":null,"abstract":"The prospect of merging the paradigms of geometric frustration on a triangular lattice and bond anisotropies in the strong spin-orbit coupling limit holds tremendous promise in the search for exotic quantum materials. Here we identify a new candidate system to realize such physics, the organic quantum antiferromagnet (CD3ND3)2NaRuCl6. We report a combination of thermodynamic, magneto-elastic and neutron scattering experiments on single-crystals to determine the phase diagram in axial magnetic fields H∥c and propose a minimal model Hamiltonian. (CD3ND3)2NaRuCl6 displays an ideal triangular arrangement of Ru3+ ions adopting the spin-orbital entangled jeff = 1/2 state. It hosts residual magnetic order below TN = 0.23 K and a highly unusual H − T phase diagram including three different incommensurate states. Spin-waves in the high-field polarized regime are described by a Heisenberg triangular lattice Hamiltonian with a potential sub-leading bond dependent anisotropy term J±±. We argue that the multi-q ground state in zero magnetic field is a prime candidate for hosting the Z2{{mathbb{Z}}}_{2} vortex crystal proposed on the triangular Heisenberg-Kitaev model. (CD3ND3)2NaRuCl6 is the first member in an extended family of quantum triangular lattice magnets, providing a new playground to study the interplay of geometric frustration and spin-orbit effects.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"159 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148286921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

引用次数: 0

Altermagnetism and weak ferromagnetism 变磁性和弱铁磁性

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-05-22 DOI: 10.1038/s41535-026-00900-9

Igor Solovyev, Sergey Nikolaev, Akihiro Tanaka

引用次数: 0

A surface-confined spiral state with the double period in the cubic chiral helimagnet Cu2OSeO3 Cu2OSeO3三次手性螺旋像中具有双周期的表面约束螺旋态

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-05-21 DOI: 10.1038/s41535-026-00892-6

Priya R. Baral, Oleg I. Utesov, Samuel H. Moody, Matthew T. Littlehales, Pierluigi Gargiani, Manuel Valvidares, Robert Cubitt, Nina-Juliane Steinke, Chen Luo, Florin Radu, Arnaud Magrez, Jonathan S. White, Victor Ukleev

{"title":"A surface-confined spiral state with the double period in the cubic chiral helimagnet Cu2OSeO3","authors":"Priya R. Baral, Oleg I. Utesov, Samuel H. Moody, Matthew T. Littlehales, Pierluigi Gargiani, Manuel Valvidares, Robert Cubitt, Nina-Juliane Steinke, Chen Luo, Florin Radu, Arnaud Magrez, Jonathan S. White, Victor Ukleev","doi":"10.1038/s41535-026-00892-6","DOIUrl":"https://doi.org/10.1038/s41535-026-00892-6","url":null,"abstract":"The chiral magnetoelectric insulator Cu2OSeO3 hosts a rich and anisotropic magnetic phase diagram that includes helical, conical, field-polarised, tilted conical, and skyrmion lattice phases. Using resonant elastic x-ray scattering (REXS), we uncover a new spiral state confined to the surface of Cu2OSeO3. This surface-confined spiral state (SSS) displays a real-space pitch of ~ 120 nm, which remarkably is twice the length of the incommensurate structures observed to-date in Cu2OSeO3. The SSS phase emerges at temperatures below 30 K when the magnetic field is applied between 3∘ to 18∘ away from the 〈110〉 crystallographic axes. Its surface localisation is demonstrated through a combination of REXS in reflection and transmission geometries, with complementary small-angle neutron scattering measurements suggesting its absence from the bulk. We attribute the stabilisation of the SSS to competing anisotropic interactions at the crystal surface. The discovery of a robust, surface-confined spiral paves the way for engineering energy-efficient, nanoscale spin-texture platforms for next-generation devices.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"159 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148286928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

引用次数: 0

The diffusion-driven orthorhombic to tetragonal transition in YBa2Cu3O7 derived with a machine learning interatomic potential 用机器学习原子间势推导了YBa2Cu3O7中扩散驱动的正交向四方跃迁

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-05-21 DOI: 10.1038/s41535-026-00891-7

Davide Gambino, Niccolò Di Eugenio, Jesper Byggmästar, Johan Klarbring, Daniele Torsello, Flyura Djurabekova, Francesco Laviano

{"title":"The diffusion-driven orthorhombic to tetragonal transition in YBa2Cu3O7 derived with a machine learning interatomic potential","authors":"Davide Gambino, Niccolò Di Eugenio, Jesper Byggmästar, Johan Klarbring, Daniele Torsello, Flyura Djurabekova, Francesco Laviano","doi":"10.1038/s41535-026-00891-7","DOIUrl":"https://doi.org/10.1038/s41535-026-00891-7","url":null,"abstract":"Defects in high-temperature superconductors such as YBa2Cu3O7 (YBCO) critically influence their superconducting behavior, as they substantially degrade or even suppress superconductivity. With the renewed interest in cuprates for next-generation superconducting magnets operating in radiation-harsh environments such as fusion reactors and particle accelerators, accurate atomistic modeling of defects and their dynamics has become essential. Here, we present a general-purpose machine-learning interatomic potential for YBCO, based on the Atomic Cluster Expansion (ACE) method and trained on density functional theory (DFT) data, with particular emphasis on defects and their diffusion mechanisms. The potential is validated against DFT calculations of ground-state properties, defect formation energies of oxygen Frenkel pairs, and diffusion barriers for their formation. Remarkably, the potential captures the diffusion-driven orthorhombic to tetragonal transition at elevated temperatures, a transformation that is difficult to describe with empirical potentials, elucidating how the formation of oxygen Frenkel pairs in the basal plane governs this order-disorder transition. The ACE potential introduced here enables large-scale, predictive atomistic simulations of defect dynamics and transport processes in YBCO, providing a powerful tool to explore its stability, performance, and functionality under realistic operating conditions. Moreover, this work proves that machine learning interatomic potentials are suitable for studies of quaternary oxides with complex chemistry.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"11 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148286929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

引用次数: 0

Nonperturbative semiclassical spin dynamics for ordered quantum magnets 有序量子磁体的非微扰半经典自旋动力学

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-05-16 DOI: 10.1038/s41535-026-00873-9

Hao Zhang, Tianyue Huang, Allen O. Scheie, Mengze Zhu, Tao Xie, N. Murai, S. Ohira-Kawamura, Andrey Zheludev, Andreas M. Läuchli, Cristian D. Batista

{"title":"Nonperturbative semiclassical spin dynamics for ordered quantum magnets","authors":"Hao Zhang, Tianyue Huang, Allen O. Scheie, Mengze Zhu, Tao Xie, N. Murai, S. Ohira-Kawamura, Andrey Zheludev, Andreas M. Läuchli, Cristian D. Batista","doi":"10.1038/s41535-026-00873-9","DOIUrl":"https://doi.org/10.1038/s41535-026-00873-9","url":null,"abstract":"In ordered quantum magnets where interactions between elementary excitations dominate over their kinetic energy, perturbative approaches often fail, making non-perturbative methods essential to capture spectral features such as bound states and the redistribution of weight within excitation continua. Although an increasing number of experiments report anomalous spin excitation continua in such systems, their microscopic interpretation remains an open challenge. Here, we investigate the spin dynamics of the triangular-lattice antiferromagnet in its 1/3-plateau phase using two complementary non-perturbative approaches: exact diagonalization in a truncated Hilbert space for a gas of elementary excitations (THED) and matrix product state (MPS) simulations. Alongside cross-validation between these methods, we benchmark our results against inelastic neutron scattering (INS) data. The THED analysis confirms the presence of two-magnon bound states and identifies the anomalous scattering continuum observed in both MPS and INS as a two-magnon resonance, arising from hybridization between the bound state and the two-magnon continuum. Furthermore, THED reveals bound states overlapping with the continuum, enriching the interpretation of continuum anomalies. More broadly, THED provides a robust framework for investigating anomalous spin excitation continua and bound-state effects in other materials with gapped spectra. Its combination of accuracy and computational efficiency makes it a powerful tool for extracting reliable microscopic models in semiclassical regimes.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"11 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148286963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

引用次数: 0

Multi-Q spin-valley order in twisted WSe2 扭曲WSe2中的多q自旋谷序

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-04-24 DOI: 10.1038/s41535-026-00884-6

Arthur Bril, Nai Chao Hu, Nick Bultinck

引用次数: 0

Anisotropic magnetoresistance and magnetic field-tunable Weyl nodes in Weyl metal SrRuO3 thin films Weyl金属SrRuO3薄膜的各向异性磁阻和磁场可调谐Weyl节点

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-04-22 DOI: 10.1038/s41535-026-00882-8

Uddipta Kar, Akhilesh Kr. Singh, Elisha Cho-Hao Lu, P. V. Sreenivasa Reddy, Fu-En Cheng, Wazid Ahmed, Song Yang, Chun-Yen Lin, Chia-Hung Hsu, Guang-Yu Guo, Wei-Li Lee

{"title":"Anisotropic magnetoresistance and magnetic field-tunable Weyl nodes in Weyl metal SrRuO3 thin films","authors":"Uddipta Kar, Akhilesh Kr. Singh, Elisha Cho-Hao Lu, P. V. Sreenivasa Reddy, Fu-En Cheng, Wazid Ahmed, Song Yang, Chun-Yen Lin, Chia-Hung Hsu, Guang-Yu Guo, Wei-Li Lee","doi":"10.1038/s41535-026-00882-8","DOIUrl":"https://doi.org/10.1038/s41535-026-00882-8","url":null,"abstract":"Weyl semimetals are a unique class of topological materials, possessing Fermi-arc surface states and exhibiting the chiral anomaly effect. The chiral anomaly refers to non-equilibrium charge transfer within a Weyl-node pair of opposite chirality under the condition of aligned electric and magnetic fields (E∥B), leading to non-conserved chiral charges and thus enhanced electrical conductivity. In experiments, such an enhanced conductivity due to the chiral anomaly manifests as a negative longitudinal magnetoresistance (MR) when the external field H is applied along the bias current direction I. In this work, we present rigorous ϕ- and α-dependent magnetotransport measurements to investigate such a negative longitudinal MR due to the chiral anomaly in a sunbeam-shaped device fabricated from an untwinned Weyl metal SrRuO3 (SRO) thin film. Here, ϕ(α) represents the angle between I and the in-plane H(SRO monoclinic [001]o). Unusual ϕ dependences of in-plane MR and Hall effects were uncovered at low temperatures, accompanied by the emergence of the fourfold-symmetric component in the in-plane MR. These results indicate that the chiral anomaly and resistivity anisotropy in SRO play important roles. In particular, the dramatic variation of Weyl nodes near the Fermi level through magnetic field manipulation of the magnetization orientation, as revealed by band structure calculations, is consistent with the observed in-plane MR and Hall effect.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"18 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147734035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

引用次数: 0

How pairing mechanism dictates topology in valley-polarized superconductors with Berry curvature 配对机制如何决定具有贝里曲率的谷极化超导体的拓扑结构

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-04-15 DOI: 10.1038/s41535-026-00878-4

Julian May-Mann, Tobias Helbig, Trithep Devakul

引用次数: 0