npj Quantum Materials最新文献

Continuum of magnetic excitations in the Kitaev honeycomb iridate D3LiIr2O6

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-29 DOI: 10.1038/s41535-025-00748-5

Thomas Halloran, Yishu Wang, K. W. Plumb, M. B. Stone, Barry Winn, M. K. Graves-Brook, J. A. Rodriguez-Rivera, Yiming Qiu, Prashant Chauhan, Johannes Knolle, Roderich Moessner, N. P. Armitage, Tomohiro Takayama, Hidenori Takagi, Collin Broholm

{"title":"Continuum of magnetic excitations in the Kitaev honeycomb iridate D3LiIr2O6","authors":"Thomas Halloran, Yishu Wang, K. W. Plumb, M. B. Stone, Barry Winn, M. K. Graves-Brook, J. A. Rodriguez-Rivera, Yiming Qiu, Prashant Chauhan, Johannes Knolle, Roderich Moessner, N. P. Armitage, Tomohiro Takayama, Hidenori Takagi, Collin Broholm","doi":"10.1038/s41535-025-00748-5","DOIUrl":"https://doi.org/10.1038/s41535-025-00748-5","url":null,"abstract":"Inelastic neutron scattering (INS) measurements of powder D3(7Li)(193Ir)2O6 reveal low energy magnetic excitations with a scattering cross-section that is broad in ∣Q∣ and energy transfer. The magnetic nature of the excitation spectrum is demonstrated by longitudinally polarized neutron scattering. The total magnetic moment of 1.8(4)μB/Ir inferred from the observed magnetic scattering cross-section is consistent with the effective moment inferred from magnetic susceptibility data and expectations for the Jeff = 1/2 single ion state. The rise in the dynamic correlation function ({mathcal{S}}(Q,omega )) for ℏω < 5 meV can be described by a simple model assuming nearest-neighbor anisotropic spin exchange, such as that found in the Kitaev model. Exchange disorder associated with the D site likely plays an important role in stabilizing the low T quantum fluctuating state1,2.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"15 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143736495","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

Magnetothermal transport in ultraclean single crystals of Kitaev magnet α-RuCl3

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-28 DOI: 10.1038/s41535-025-00749-4

Y. Xing, R. Namba, K. Imamura, K. Ishihara, S. Suetsugu, T. Asaba, K. Hashimoto, T. Shibauchi, Y. Matsuda, Y. Kasahara

{"title":"Magnetothermal transport in ultraclean single crystals of Kitaev magnet α-RuCl3","authors":"Y. Xing, R. Namba, K. Imamura, K. Ishihara, S. Suetsugu, T. Asaba, K. Hashimoto, T. Shibauchi, Y. Matsuda, Y. Kasahara","doi":"10.1038/s41535-025-00749-4","DOIUrl":"https://doi.org/10.1038/s41535-025-00749-4","url":null,"abstract":"The layered honeycomb magnet α-RuCl3 has emerged as a promising candidate for realizing a Kitaev quantum spin liquid. Previous studies have reported oscillation-like anomalies in the longitudinal thermal conductivity and half-integer quantized thermal Hall conductivity above the antiferromagnetic critical field Hc, generating significant interest. However, the origins of these phenomena remain contentious due to strong sample dependence. Here we re-examine the magnetothermal transport properties using recently available ultra-pure α-RuCl3 single crystals to further elucidate potential signatures of the spin liquid state. Our findings reveal that while anomalies in thermal conductivity above Hc persist even in ultraclean crystals, their magnitude is significantly attenuated, contrary to the quantum oscillations hypothesis. This suggests that the anomalies are likely attributable to localized stacking faults inadvertently introduced during magnetothermal transport measurements. The thermal Hall conductivity exhibits a half-quantized plateau, albeit with a narrower width than previously reported. This width reduction can be understood through two distinct mechanisms: sample-dependent magnetic critical fields that influence the lower boundary of the plateau region, and the decoupling between chiral Majorana edge currents and phononic thermal transport that determines the upper boundary. These results indicate that structural imperfections exert a substantial influence on both the oscillation-like anomalies and quantization effects observed in magnetothermal transport measurements of α-RuCl3.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"49 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723474","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

Metastable photo-induced superconductivity far above Tc

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-28 DOI: 10.1038/s41535-025-00750-x

Sambuddha Chattopadhyay, Christian J. Eckhardt, Dante M. Kennes, Michael A. Sentef, Dongbin Shin, Angel Rubio, Andrea Cavalleri, Eugene A. Demler, Marios H. Michael

{"title":"Metastable photo-induced superconductivity far above Tc","authors":"Sambuddha Chattopadhyay, Christian J. Eckhardt, Dante M. Kennes, Michael A. Sentef, Dongbin Shin, Angel Rubio, Andrea Cavalleri, Eugene A. Demler, Marios H. Michael","doi":"10.1038/s41535-025-00750-x","DOIUrl":"https://doi.org/10.1038/s41535-025-00750-x","url":null,"abstract":"Inspired by the striking discovery of metastable superconductivity in K3C60 at 100K, far above Tc = 20 K, we discuss possible mechanisms for long-lived, photo-induced superconductivity. Starting from a model of optically-driven Raman phonons coupled to inter-band electronic transitions, we develop a microscopic mechanism for photo-controlling the pairing interaction. Leveraging this mechanism, we first investigate long-lived superconductivity arising from the thermodynamic metastable trapping of the driven phonon. We then propose an alternative route, where the superconducting gap created by an optical drive leads to a dynamical bottleneck in the equilibration of quasi-particles. We conclude by discussing the implications of both scenarios for experiments that can be used to discriminate between them. Our work provides falsifiable explanations for the nanosecond-scale photo-induced superconductivity found in K3C60, while simultaneously offering a theoretical basis for exploring metastable superconductivity in other quantum materials.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"36 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734105","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

Tensor network study of the light-induced phase transitions in vanadium dioxide

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-24 DOI: 10.1038/s41535-025-00751-w

Lin Zhang, Utso Bhattacharya, Maria Recasens, Tobias Grass, Ravindra W. Chhajlany, Maciej Lewenstein, Allan S. Johnson

{"title":"Tensor network study of the light-induced phase transitions in vanadium dioxide","authors":"Lin Zhang, Utso Bhattacharya, Maria Recasens, Tobias Grass, Ravindra W. Chhajlany, Maciej Lewenstein, Allan S. Johnson","doi":"10.1038/s41535-025-00751-w","DOIUrl":"https://doi.org/10.1038/s41535-025-00751-w","url":null,"abstract":"Vanadium dioxide (VO2) is a prototypical material that undergoes a structural phase transition (SPT) from a monoclinic (M1) to rutile (R) structure and an insulator-to-metal transition (IMT) when heated above 340 K or excited by an ultrafast laser pulse. Due to the strong electron–electron and electron–lattice interactions, modeling the ultrafast IMT in VO2 has proven challenging. Here, we develop an efficient theoretical approach to the light-induced phase transitions by combining a tensor network ansatz for the electrons with a semiclassical description of the nuclei. Our method is based on a quasi-one-dimensional model for the material with the important multiorbital character, electron–lattice coupling, and electron–electron correlations being included. We benchmark our method by showing that it qualitatively captures the ground state phase diagram and finite-temperature phase transitions of VO2. Then, we use the hybrid quantum-classical tensor network approach to simulate the dynamics following photoexcitation. We find that the structure can transform faster than the harmonic phonon modes of the M1 phase, suggesting lattice nonlinearity is key in the SPT. We also find separate timescales in the evolution of dimerization and tilt lattice distortions, as well as the loss and subsequent partial restoration behavior of the displacements, explaining the complex dynamics observed in recent experiments. Moreover, decoupled SPT and IMT dynamics are observed, with the IMT occurs quasi-instantaneously. Our model and approach, which can be extended to a wide range of materials, reveal the unexpected non-monotonic transformation pathways in VO2 and pave the way for future studies of non-thermal phase transformations in quantum materials.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"35 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143677718","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

Flat band physics in the charge-density wave state of 1T-TaS2 and 1T-TaSe2

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-20 DOI: 10.1038/s41535-025-00747-6

Amir Dalal, Jonathan Ruhman, Jörn W. F. Venderbos

引用次数: 0

Light-induced charge and spin Hall currents in materials with C4K symmetry

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-18 DOI: 10.1038/s41535-025-00746-7

T. Farajollahpour, R. Ganesh, K. V. Samokhin

引用次数: 0

Topological excitations at time vortices in periodically driven systems

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-13 DOI: 10.1038/s41535-025-00745-8

Gilad Kishony, Ori Grossman, Netanel Lindner, Mark Rudner, Erez Berg

引用次数: 0

Giant tunability of superlattice excitations in chiral Cr1/3TaS2

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-03 DOI: 10.1038/s41535-025-00734-x

J. L. Musfeldt, Y. Gu, J. T. Haraldsen, K. Du, P. Yapa, J. Yang, D. G. Mandrus, S. -W. Cheong, Z. Liu

{"title":"Giant tunability of superlattice excitations in chiral Cr1/3TaS2","authors":"J. L. Musfeldt, Y. Gu, J. T. Haraldsen, K. Du, P. Yapa, J. Yang, D. G. Mandrus, S. -W. Cheong, Z. Liu","doi":"10.1038/s41535-025-00734-x","DOIUrl":"https://doi.org/10.1038/s41535-025-00734-x","url":null,"abstract":"Layered chalcogenides are superb platforms for exploring tunable functionality and the impact of external stimuli, and when intercalated with metal atoms, there are opportunities to reveal unique guest–host interactions. One barrier to greater control of the collective metal monolayer excitations in these materials is the absence of detailed information about how they evolve under compression. In order to explore superlattice excitations in a series of intercalated chalcogenides, we measured the Raman scattering response of Cr1/3TaS2 under pressure and compared our findings with the behavior of Cr1/3NbS2, Fe1/3TaS2, and Fe1/4TaS2. Overall, we find that the metal monolayer excitations are sharp and strong, spanning a significant portion of the teraHertz range. Analysis reveals that chalcogen layer thickness and size of the van der Waals gap to that of the A site ion are sufficient to divide these materials into two classes: the Cr analogs with relatively little distortion of the metal monolayer excitations under compression and the Fe analogs that host substantial symmetry breaking. In addition to unraveling these structure-property relations, we combine pressure and strain to demonstrate that the superlattice excitation in Cr1/3TaS2 can be tuned in a nearly linear fashion by approximately 16% overall in frequency space—a significant advance for spintronics and photonics applications.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"25 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532633","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

Microscopic roadmap to a Kitaev-Yao-Lee spin-orbital liquid

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-03-01 DOI: 10.1038/s41535-025-00744-9

Derek Churchill, Emily Z. Zhang, Hae-Young Kee

{"title":"Microscopic roadmap to a Kitaev-Yao-Lee spin-orbital liquid","authors":"Derek Churchill, Emily Z. Zhang, Hae-Young Kee","doi":"10.1038/s41535-025-00744-9","DOIUrl":"https://doi.org/10.1038/s41535-025-00744-9","url":null,"abstract":"The exactly solvable spin-1/2 Kitaev model on a honeycomb lattice has drawn significant interest, as it offers a pathway to realizing the long-sought-after quantum spin liquid. Building upon the Kitaev model, Yao and Lee introduced another exactly solvable model on an unusual star lattice featuring non-abelian spinons. The additional pseudospin degrees of freedom in this model could provide greater stability against perturbations, making this model appealing. However, a mechanism to realize such an interaction in a standard honeycomb lattice remains unknown. Here, we provide a microscopic theory to obtain the Yao-Lee model, on a honeycomb lattice by utilizing strong spin-orbit coupling of anions edge-shared between two eg ions in the exchange processes. This mechanism leads to the desired bond-dependent interaction among spins rather than orbitals, unique to our model, implying that the orbitals fractionalize into gapless Majorana fermions and fermionic octupolar excitations emerge. Since the conventional Kugel-Khomskii interaction also appears, we examine the phase diagram, including these interactions, using classical Monte Carlo simulations and exact diagonalization techniques. Our findings reveal a broad region of disordered states that break rotational symmetry in the bond energy, suggesting intriguing behavior reminiscent of a spin-orbital liquid.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"33 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526177","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

Fate of transient order parameter domain walls in ultrafast experiments

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2025-02-27 DOI: 10.1038/s41535-025-00743-w

Lingxian Kong, Ryuichi Shindou, Zhiyuan Sun

{"title":"Fate of transient order parameter domain walls in ultrafast experiments","authors":"Lingxian Kong, Ryuichi Shindou, Zhiyuan Sun","doi":"10.1038/s41535-025-00743-w","DOIUrl":"https://doi.org/10.1038/s41535-025-00743-w","url":null,"abstract":"In ultrafast experiments, an optical pump pulse often generates transient domain walls of the order parameter in materials with spontaneous symmetry breaking, due to either a finite penetration depth of light on a three-dimensional (3D) material, or a finite spot size on a two-dimensional (2D) material. We show that the domain wall decays due to unstable order parameter fluctuations. We study a generic system with U(1)-symmetric order, and those with an additional weak Z2 (U(1)-symmetry-breaking) term, representing the charge-density-wave (CDW) orders in recent experiments. During the first stage of the decay dynamics, exponentially growing thermal fluctuations convert the domain wall into an interface with randomly distributed topological defects. In the second stage, the topological defects undergo a coarsening dynamics within the interface. For a 2D interface in a 3D system, the coarsening dynamics leads to a diffusive growth of the correlation length. For a one-dimensional (1D) interface in a 2D system with the weak Z2 term, the correlation-length growth shows a crossover from diffusive to sub-diffusive behavior.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"6 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506800","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