Pub Date : 2025-12-26DOI: 10.1038/s41535-025-00838-4
Stephen Zhang, Danrui Ni, Ruyi Ke, Guangming Cheng, Nan Yao, Robert J. Cava
Superconductivity in La4Ni3O10 has been reported to emerge upon suppression of intertwined spin and charge density wave (SDW/CDW) order, suggesting a possible connection to the pairing mechanism. Here we report a systematic investigation of La4 Ni3−xCux O10+δ ((0le xle 0.7)), focusing on the evolution of the SDW/CDW order as a function of chemical substitution. Temperature-dependent resistivity, magnetic susceptibility, and Hall effect measurements reveal a linear suppression of density wave transition temperature Tdw and a concurrent enhancement of hole concentration with increasing Cu content. At higher substitution levels ((x > 0.15)), the transition induced anomaly in the resistivity becomes undetectable while a magnetic signature persists, indicating a partial decoupling of spin and charge components and the possible survival of short-range spin correlations. The absence of superconductivity across the substitution series highlights the importance of additional factors in stabilizing the superconducting state in pressurized La4Ni3O10.
{"title":"Suppression of intertwined density waves in La4Ni3-xCuxO10+δ","authors":"Stephen Zhang, Danrui Ni, Ruyi Ke, Guangming Cheng, Nan Yao, Robert J. Cava","doi":"10.1038/s41535-025-00838-4","DOIUrl":"https://doi.org/10.1038/s41535-025-00838-4","url":null,"abstract":"Superconductivity in La4Ni3O10 has been reported to emerge upon suppression of intertwined spin and charge density wave (SDW/CDW) order, suggesting a possible connection to the pairing mechanism. Here we report a systematic investigation of La4 Ni3−xCux O10+δ ((0le xle 0.7)), focusing on the evolution of the SDW/CDW order as a function of chemical substitution. Temperature-dependent resistivity, magnetic susceptibility, and Hall effect measurements reveal a linear suppression of density wave transition temperature Tdw and a concurrent enhancement of hole concentration with increasing Cu content. At higher substitution levels ((x > 0.15)), the transition induced anomaly in the resistivity becomes undetectable while a magnetic signature persists, indicating a partial decoupling of spin and charge components and the possible survival of short-range spin correlations. The absence of superconductivity across the substitution series highlights the importance of additional factors in stabilizing the superconducting state in pressurized La4Ni3O10.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"28 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894251","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}
Nonvolatile optical manipulation of material properties on demand is a highly sought-after feature in the advancement of future optoelectronic applications. Here, we unravel the nature of the single-laser-pulse induced hidden state in 1T-TaS2 by systematically investigating the electronic structure evolution and the pulse-pair control throughout the reversible transition cycle. Our data indicate a mixed-stacking state involving two similarly low-energy interlayer orders, which is manifested as the charge density wave phase disruption. Furthermore, we elucidate distinct mechanisms underlying the bidirectional transformations — the ultrafast formation of the hidden state is initiated by a coherent phonon which triggers a competition between interlayer stacking orders, while its recovery is governed by the progressive domain evolution. Our work highlights the deterministic role of the competing interlayer orders in the nonvolatile phase transition in 1T-TaS2, establishing all-optical engineering of stacking orders in low-dimensional materials as a viable strategy for achieving desirable nonvolatile electronic devices.
{"title":"Nonvolatile optical control of interlayer stacking order in 1T-TaS2","authors":"Junde Liu, Pei Liu, Liu Yang, Sung-Hoon Lee, Mojun Pan, Famin Chen, Jierui Huang, Bei Jiang, Mingzhe Hu, Yuchong Zhang, Zhaoyang Xie, Gang Wang, Mengxue Guan, Wei Jiang, Huaixin Yang, Jianqi Li, Chenxia Yun, Zhiwei Wang, Sheng Meng, Yugui Yao, Tian Qian, Xun Shi","doi":"10.1038/s41535-025-00836-6","DOIUrl":"https://doi.org/10.1038/s41535-025-00836-6","url":null,"abstract":"Nonvolatile optical manipulation of material properties on demand is a highly sought-after feature in the advancement of future optoelectronic applications. Here, we unravel the nature of the single-laser-pulse induced hidden state in 1T-TaS2 by systematically investigating the electronic structure evolution and the pulse-pair control throughout the reversible transition cycle. Our data indicate a mixed-stacking state involving two similarly low-energy interlayer orders, which is manifested as the charge density wave phase disruption. Furthermore, we elucidate distinct mechanisms underlying the bidirectional transformations — the ultrafast formation of the hidden state is initiated by a coherent phonon which triggers a competition between interlayer stacking orders, while its recovery is governed by the progressive domain evolution. Our work highlights the deterministic role of the competing interlayer orders in the nonvolatile phase transition in 1T-TaS2, establishing all-optical engineering of stacking orders in low-dimensional materials as a viable strategy for achieving desirable nonvolatile electronic devices.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"25 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145808183","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}
Pub Date : 2025-12-17DOI: 10.1038/s41535-025-00839-3
Lingfei Zhang, Takahiro C. Fujita, Masashi Kawasaki
Two-dimensional electrons formed at the heterointerfaces of transition metal oxides have been the focus of intensive studies in condensed matter physics since their discovery at LaAlO3/SrTiO3. In particular, various attempts have been made to integrate magnetic properties with such two-dimensional electrons, aiming at exploring spintronic functions. Here we demonstrate a novel approach to realize the spin-polarized two-dimensional electron system at the LaAlO3/SrTiO3 interface by the proximity effect of emergent magnetic fields from adjacent DyFeO3. We observed an unconventional anomalous Hall effect with a remarkable Hall angle of ~20%, resulting from the combination of high-mobility carriers in LaAlO3/SrTiO3 and the emergent magnetic fields from non-coplanar canted antiferromagnetic spin textures in DyFeO3. These findings demonstrate a viable route toward oxide‑based spintronic functionalities by exploiting proximity‑induced emergent fields in two‑dimensional electron systems.
{"title":"Giant unconventional Hall effect in DyFeO3/LaAlO3/SrTiO3 two-dimensional electron system via proximity-induced emergent field","authors":"Lingfei Zhang, Takahiro C. Fujita, Masashi Kawasaki","doi":"10.1038/s41535-025-00839-3","DOIUrl":"https://doi.org/10.1038/s41535-025-00839-3","url":null,"abstract":"Two-dimensional electrons formed at the heterointerfaces of transition metal oxides have been the focus of intensive studies in condensed matter physics since their discovery at LaAlO3/SrTiO3. In particular, various attempts have been made to integrate magnetic properties with such two-dimensional electrons, aiming at exploring spintronic functions. Here we demonstrate a novel approach to realize the spin-polarized two-dimensional electron system at the LaAlO3/SrTiO3 interface by the proximity effect of emergent magnetic fields from adjacent DyFeO3. We observed an unconventional anomalous Hall effect with a remarkable Hall angle of ~20%, resulting from the combination of high-mobility carriers in LaAlO3/SrTiO3 and the emergent magnetic fields from non-coplanar canted antiferromagnetic spin textures in DyFeO3. These findings demonstrate a viable route toward oxide‑based spintronic functionalities by exploiting proximity‑induced emergent fields in two‑dimensional electron systems.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"9 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145765578","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}
Band convergence has been utilized as an effective strategy to enhance the Seebeck coefficient, typically by improving the energy dependence of carrier density near the Fermi level. In contrast, the energy dependence of carrier mobility, which can also enhance the Seebeck coefficient, has attracted less attention. Here, we show that the Seebeck coefficient can be improved when the additional converging band contributes highly mobile carriers, even if they have minimal impact on carrier density. The high-mobility carriers enhance the net diffusion flux, promoting carrier accumulation and amplifying the Seebeck voltage. This mobility-driven enhancement exhibits a hump-like feature in the Pisarenko plot, which becomes flatter and shifts toward lower carrier concentrations as the bands approach. The transport properties of p-type rhombohedral GeTe, as a potential case, were experimentally examined. This work deepens the understanding of band convergence-induced Seebeck coefficient enhancement in thermoelectric materials.
{"title":"Highly mobile carrier-driven Seebeck coefficient enhancement","authors":"Yu Liu, Min Zhang, Lirong Hu, Ziheng Gao, Tianqi Deng, Chenguang Fu, Tiejun Zhu","doi":"10.1038/s41535-025-00837-5","DOIUrl":"https://doi.org/10.1038/s41535-025-00837-5","url":null,"abstract":"Band convergence has been utilized as an effective strategy to enhance the Seebeck coefficient, typically by improving the energy dependence of carrier density near the Fermi level. In contrast, the energy dependence of carrier mobility, which can also enhance the Seebeck coefficient, has attracted less attention. Here, we show that the Seebeck coefficient can be improved when the additional converging band contributes highly mobile carriers, even if they have minimal impact on carrier density. The high-mobility carriers enhance the net diffusion flux, promoting carrier accumulation and amplifying the Seebeck voltage. This mobility-driven enhancement exhibits a hump-like feature in the Pisarenko plot, which becomes flatter and shifts toward lower carrier concentrations as the bands approach. The transport properties of p-type rhombohedral GeTe, as a potential case, were experimentally examined. This work deepens the understanding of band convergence-induced Seebeck coefficient enhancement in thermoelectric materials.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"167 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145765608","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}
Pub Date : 2025-12-15DOI: 10.1038/s41535-025-00834-8
F. Elson, J. Philippe, G. Simutis, O. K. Forslund, M. Abdel-Hafiez, M. Janoschek, R. Khasanov, D. Das, J. Weissenrieder, D. W. Tam, Y. Sassa, M. Månsson
Superconductivity in TiSe2 emerges when the charge density wave (CDW) order is suppressed under pressure or doping. Recent theoretical and experimental studies suggest that a Lifshitz transition plays a key role in stabilizing the superconducting phase. Here, we present muon spin resonance measurements of pressurized TiSe2, revealing a two-gap superconducting state. Our results indicate that the smaller gap contributes unexpectedly strongly to the total superfluid density. This effect is consistent with an enhanced density of states in a newly formed Fermi surface pocket at the Lifshitz transition. These findings provide microscopic insight into the interplay between CDW suppression, Fermi surface reconstruction, and multi-gap superconductivity in TiSe2, demonstrating how pressure-induced changes in electronic structure can shape superconducting properties in layered materials.
{"title":"Lifshitz-enhanced superfluid density in two-gap superconducting TiSe2","authors":"F. Elson, J. Philippe, G. Simutis, O. K. Forslund, M. Abdel-Hafiez, M. Janoschek, R. Khasanov, D. Das, J. Weissenrieder, D. W. Tam, Y. Sassa, M. Månsson","doi":"10.1038/s41535-025-00834-8","DOIUrl":"https://doi.org/10.1038/s41535-025-00834-8","url":null,"abstract":"Superconductivity in TiSe2 emerges when the charge density wave (CDW) order is suppressed under pressure or doping. Recent theoretical and experimental studies suggest that a Lifshitz transition plays a key role in stabilizing the superconducting phase. Here, we present muon spin resonance measurements of pressurized TiSe2, revealing a two-gap superconducting state. Our results indicate that the smaller gap contributes unexpectedly strongly to the total superfluid density. This effect is consistent with an enhanced density of states in a newly formed Fermi surface pocket at the Lifshitz transition. These findings provide microscopic insight into the interplay between CDW suppression, Fermi surface reconstruction, and multi-gap superconductivity in TiSe2, demonstrating how pressure-induced changes in electronic structure can shape superconducting properties in layered materials.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"158 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759429","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}
Pub Date : 2025-12-04DOI: 10.1038/s41535-025-00833-9
Sabrina J. Li, Guru Khalsa, Jeffrey Z. Kaaret, Nicole A. Benedek
Experiments involving resonant optical excitation of infrared-active phonons in crystals have emerged as a powerful new way to tune materials properties. A puzzling and so far unexplained aspect of some so-called nonlinear phononics experiments is that the observed lifetimes of the optically created metastable phases are sometimes orders of magnitude longer than expected based on the nonlinear phononics mechanism assumed in most works. We use a combination of phenomenological theory and first-principles calculations to demonstrate that strong coupling between different lattice degrees of freedom (strains and Raman-active phonons) can give rise to a long-lived metastable phase recently observed in experiments on perovskite LaAlO 3 [Hortensius et al. npj Quantum Mater . 5 95 (2020)]. We show that the long-timescale oscillatory response in the experimental optical reflectivity data is not due solely to shear strains, as originally suggested, but arises from a “hybrid” mode involving displacements of Raman-active phonons of the same symmetry. Our work suggests that strong coupling between different order parameters can provide a mechanism for long-lived optically created metastable phases and points towards strategies, such as strain engineering, for modifying or increasing the lifetime of light-induced phases in ultrafast optical experiments.
涉及晶体中红外主动声子的共振光学激发的实验已经成为调节材料性质的一种强大的新方法。在一些所谓的非线性声子实验中，一个令人困惑和至今无法解释的方面是，根据大多数工作中假设的非线性声子机制，观察到的光学产生的亚稳相的寿命有时比预期的长几个数量级。我们使用现象学理论和第一原理计算的结合来证明不同晶格自由度（应变和拉曼活跃声子）之间的强耦合可以产生最近在钙钛矿LaAlO 3实验中观察到的长寿命亚稳相[Hortensius et al. npj Quantum Mater]。[5][95]（2020）。我们表明，实验光学反射率数据中的长时间振荡响应并不像最初提出的那样仅仅是由于剪切应变，而是由于涉及相同对称性的拉曼主动声子位移的“混合”模式。我们的研究表明，不同阶参量之间的强耦合可以为长寿命的光学创建亚稳相提供一种机制，并指出了在超快光学实验中修改或增加光诱导相寿命的策略，如应变工程。
{"title":"Understanding long-lived metastable phases in ultrafast optical experiments","authors":"Sabrina J. Li, Guru Khalsa, Jeffrey Z. Kaaret, Nicole A. Benedek","doi":"10.1038/s41535-025-00833-9","DOIUrl":"https://doi.org/10.1038/s41535-025-00833-9","url":null,"abstract":"Experiments involving resonant optical excitation of infrared-active phonons in crystals have emerged as a powerful new way to tune materials properties. A puzzling and so far unexplained aspect of some so-called nonlinear phononics experiments is that the observed lifetimes of the optically created metastable phases are sometimes orders of magnitude longer than expected based on the nonlinear phononics mechanism assumed in most works. We use a combination of phenomenological theory and first-principles calculations to demonstrate that strong coupling between different lattice degrees of freedom (strains and Raman-active phonons) can give rise to a long-lived metastable phase recently observed in experiments on perovskite LaAlO <jats:sub>3</jats:sub> [Hortensius et al. <jats:italic>npj Quantum Mater</jats:italic> . 5 95 (2020)]. We show that the long-timescale oscillatory response in the experimental optical reflectivity data is not due solely to shear strains, as originally suggested, but arises from a “hybrid” mode involving displacements of Raman-active phonons of the same symmetry. Our work suggests that strong coupling between different order parameters can provide a mechanism for long-lived optically created metastable phases and points towards strategies, such as strain engineering, for modifying or increasing the lifetime of light-induced phases in ultrafast optical experiments.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"216 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145664961","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}
Pub Date : 2025-12-03DOI: 10.1038/s41535-025-00815-x
Changle Liu, Guijing Duan, Rong Yu
{"title":"Theory of rare-earth Kramers magnets on a shastry-sutherland lattice: dimer phases in the presence of strong spin-orbit coupling","authors":"Changle Liu, Guijing Duan, Rong Yu","doi":"10.1038/s41535-025-00815-x","DOIUrl":"https://doi.org/10.1038/s41535-025-00815-x","url":null,"abstract":"","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"1 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145664770","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}
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