npj Quantum Materials最新文献_第2页

Successive spin reorientations and multi-k magnetism in A-site ordered perovskites RBaFe2O6 a位有序钙钛矿RBaFe2O6的连续自旋取向和多k磁性

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-09-01 DOI: 10.1038/s41535-026-00941-0

K. Ji, M. Goto, M. Iihoshi, Z. Tan, P. Miao, P. Manuel, J. Paul Attfield, Y. Shimakawa

{"title":"Successive spin reorientations and multi-k magnetism in A-site ordered perovskites RBaFe2O6","authors":"K. Ji, M. Goto, M. Iihoshi, Z. Tan, P. Miao, P. Manuel, J. Paul Attfield, Y. Shimakawa","doi":"10.1038/s41535-026-00941-0","DOIUrl":"https://doi.org/10.1038/s41535-026-00941-0","url":null,"abstract":"The A-site layered double perovskite RBaFe2O6 (R = Pr, Nd, Sm) containing the unusually high-valent Fe3.5+ state exhibits a cascade of charge-disproportionation (CD) transitions on cooling driven by competing electronic instabilities: 2Fe3.5+ → Fe3+ + Fe4+ → 1.5Fe3+ + 0.5Fe5+. Using neutron powder diffraction and magnetisation measurements, we determine the evolution of magnetic structures across these successive CD regimes. NdBaFe2O6 and SmBaFe2O6 exhibit two successive spin reorientation transitions, with the ordered moments reorienting between crystallographic directions before stabilising in a low-temperature multi-k (Γ + Y) magnetic state. In contrast, PrBaFe2O6 undergoes a direct spin reorientation without an intermediate phase, while a weak Y component is already present near the ordering temperature. These results show that the magnetic evolution closely follows the CD progression and is consistent with changes in exchange topology and magnetocrystalline anisotropy, leading to spin reorientation and multi-k magnetism. RBaFe2O6 thus provides a model system in which charge redistribution directly controls complex magnetic order in high-valent Fe oxides.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"17 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148899515","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

Automated electrostatic characterization of quantum dot devices in single- and bilayer heterostructures 单层和双层异质结构中量子点器件的自动静电特性

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-09-01 DOI: 10.1038/s41535-026-00921-4

Merritt P. R. Losert, Dario Denora, Barnaby van Straaten, Stefan D. Oosterhout, Lucas Stehouwer, Giordano Scappucci, Menno Veldhorst, Justyna P. Zwolak

{"title":"Automated electrostatic characterization of quantum dot devices in single- and bilayer heterostructures","authors":"Merritt P. R. Losert, Dario Denora, Barnaby van Straaten, Stefan D. Oosterhout, Lucas Stehouwer, Giordano Scappucci, Menno Veldhorst, Justyna P. Zwolak","doi":"10.1038/s41535-026-00921-4","DOIUrl":"https://doi.org/10.1038/s41535-026-00921-4","url":null,"abstract":"As quantum dot (QD)-based spin qubits advance toward larger, more complex device architectures, rapid, automated characterization and data analysis tools become critical. The orientation and spacing of transition lines in a charge stability diagram (CSD) contain a fingerprint of a QD device’s capacitive environment, making these measurements useful tools for device characterization. However, manually interpreting these features is time-consuming, error-prone, and impractical at scale. Here, we present the Automated Characterization of Capacitive Environment for Testing, Optimization, and Reconstruction (ACCENTOR) protocol for extracting underlying capacitive properties from CSDs. Our method combines machine-learning-based segmentation, geometric reconstruction, and transition tracking to identify and analyze charge transitions across large CSD datasets without manual annotation. We demonstrate this method using experimentally measured data from QD devices: a strained-germanium single-quantum-well (planar) and a strained-germanium double-quantum-well (bilayer). Unlike for planar QD devices, CSDs in bilayer germanium heterostructure exhibit a larger set of transitions, including interlayer tunneling and distinct loading lines for the vertically stacked QDs, making them a powerful testbed for automation methods. By analyzing series of CSDs, ACCENTOR estimates physically relevant quantities, including relative lever arms and capacitive couplings, enabling rapid electrostatic characterization of QD devices.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"145 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148899517","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

Distinct lattice and charge excitations in AV3Sb5 kagome superconductors AV3Sb5 kagome超导体中不同的晶格和电荷激励

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-31 DOI: 10.1038/s41535-026-00937-w

Dongjin Oh, Stefan Enzner, Lennart Klebl, Harley D. Scammell, Julian Ingham, Tim Wehling, Giorgio Sangiovanni, Ronny Thomale, Ahmet Kemal Demir, Connor Occhialini, Dirk Wulferding, Ziqiang Wang, Andrea Capa Salinas, Stephen D. Wilson, Riccardo Comin

{"title":"Distinct lattice and charge excitations in AV3Sb5 kagome superconductors","authors":"Dongjin Oh, Stefan Enzner, Lennart Klebl, Harley D. Scammell, Julian Ingham, Tim Wehling, Giorgio Sangiovanni, Ronny Thomale, Ahmet Kemal Demir, Connor Occhialini, Dirk Wulferding, Ziqiang Wang, Andrea Capa Salinas, Stephen D. Wilson, Riccardo Comin","doi":"10.1038/s41535-026-00937-w","DOIUrl":"https://doi.org/10.1038/s41535-026-00937-w","url":null,"abstract":"The kagome superconductor family AV3Sb5 (A = Cs, Rb, K) provides a rich platform for exploring diverse electronic symmetry breaking phenomena, including superconductivity and various forms of density wave orders. Although these compounds share the identical lattice structure in the normal state, they exhibit distinct forms of symmetry breaking upon entering the charge density wave (CDW) phase, and the microscopic origin of which remain elusive. Here, we investigate the lattice and charge degrees of freedom in AV3Sb5 using angle-resolved polarized Raman spectroscopy. Our comprehensive polarization-resolved measurements reveal that the lifting of the twofold-degeneracy of the E2g phonon mode in the CDW phase, previously reported only in CsV3Sb5 with a 3 GHz splitting, also appears ubiquitously in the other two compounds. In contrast, the collective CDW excitations exhibit markedly different polarization dependences depending on the alkali-metal species. These distinct behaviors in the lattice and charge channels provide crucial insight into the enigmatic material-dependent symmetry breaking phenomena that appear in the CDW phase. Furthermore, our experiments, together with first-principles calculations and an effective Hamiltonian model, shed light on the nature of the charge order structure in AV3Sb5 kagome superconductors.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"235 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148899516","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

Two-dimensional coherent spectroscopy of CoNb2O6 CoNb2O6的二维相干光谱

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-20 DOI: 10.1038/s41535-026-00936-x

Yoshito Watanabe, Simon Trebst, Ciarán Hickey

{"title":"Two-dimensional coherent spectroscopy of CoNb2O6","authors":"Yoshito Watanabe, Simon Trebst, Ciarán Hickey","doi":"10.1038/s41535-026-00936-x","DOIUrl":"https://doi.org/10.1038/s41535-026-00936-x","url":null,"abstract":"With recent advances in terahertz (THz) sources and detection, two-dimensional coherent spectroscopy (2DCS), which allows one to probe nonlinear responses, now reaches the meV regime relevant for quasiparticle excitations in magnetic materials. This opens a promising route to reveal many-body phenomena that evade linear-response probes. To date, most experimental applications have focused on classical magnets, and a solid demonstration in a quantum magnet has yet to be established. Here we present a theoretical study of 2DCS in CoNb2O6, a quasi-one-dimensional Ising magnet that is believed to host fractionalized spinons which at low temperatures are confined by weak interchain coupling. Our analysis, which builds on an experimentally constrained effective S = 1/2 Hamiltonian, is found to reveal unambiguous 2DCS signatures of spinon deconfinement above the low-temperature ordered phase. Using a four-spinon approximation, we track these 2DCS signatures by sequentially building a faithful microscopic model for CoNb2O6, starting from the exactly solvable one-dimensional transverse-field Ising model (1d TFIM) and successively adding additional interactions. In particular, adding a bond-dependent staggered YZ interaction to the 1d-TFIM already reproduces many key spectral features of the full material Hamiltonian. Within this TFIM+YZ model, we find a series of bound states, including a four-spinon bound state that is distinct from the familiar two-spinon bound states. We further find that introducing a confinement potential suppresses sharp spinon-echo features, which are thought to reflect an underlying continuum of fractionalized excitations. Our results provide concrete predictions for future THz 2DCS experiments on CoNb2O6 and related quasi-one-dimensional quantum magnets.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"19 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148769280","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

Anisotropic Kitaev spin glass in Li2RuxIr1−xO3 Li2RuxIr1−xO3的各向异性Kitaev自旋玻璃

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-19 DOI: 10.1038/s41535-026-00935-y

Mayia A. Vranas, Alejandro Ruiz, Vikram Nagarajan, Erik S. Lamb, Gerald D. Morris, Zahir Islam, Christie Nelson, Nobumichi Tamura, Benjamin A. Frandsen, James G. Analytis, Alex Frano

{"title":"Anisotropic Kitaev spin glass in Li2RuxIr1−xO3","authors":"Mayia A. Vranas, Alejandro Ruiz, Vikram Nagarajan, Erik S. Lamb, Gerald D. Morris, Zahir Islam, Christie Nelson, Nobumichi Tamura, Benjamin A. Frandsen, James G. Analytis, Alex Frano","doi":"10.1038/s41535-026-00935-y","DOIUrl":"https://doi.org/10.1038/s41535-026-00935-y","url":null,"abstract":"Kitaev iridates are an important class of spin-orbit-entangled quantum materials, where bond-directional exchange generates strong magnetic frustration and unconventional correlated states. The α, β, γ − Li2IrO3 family exhibit fragile and highly anisotropic magnetic behavior, including incommensurate counter-rotating order, strong field sensitivity, and pressure-driven electronic reconstruction. Understanding how chemical substitution perturbs these competing interactions provides a route toward probing the underlying frustrated magnetic state. Here, we study single crystals of β − Li2RuxIr1−xO3 with dilute Ru substitution, x ≲ 10%. Through magnetometry, resonant elastic X-ray scattering, ac-heat capacity, and muon spin relaxation/rotation, we show that weak magnetic disorder suppresses the incommensurate antiferromagnetic ground state. Instead, the system evolves into a bulk spin glass characterized by slow relaxation and frozen, local magnetic fields. Despite the loss of long-range order, the glassy state retains substantial directional anisotropy, evidenced by enhanced b-axis magnetic susceptibility and direction-dependent thermoremanent relaxation. Structural probes further indicate that Ru substitution leaves the hyperhoneycomb lattice largely undistorted while disrupting magnetic coherence, suggesting that disorder freezes spins within a still-active bond-directional exchange environment. In this picture, dilute Ru substitution provides a controlled pathway into an anisotropic Kitaev spin glass regime that preserves essential fingerprints of the underlying Kitaev exchange network.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"1 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148769282","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

Superconductivity from doping symmetric mass generation insulators: application to La3Ni2O7 under pressure 掺杂对称质量生成绝缘子的超导性：在压力下La3Ni2O7上的应用

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-17 DOI: 10.1038/s41535-026-00925-0

Da-Chuan Lu, Miao Li, Zhao-Yi Zeng, Wanda Hou, Juven Wang, Fan Yang, Yi-Zhuang You

{"title":"Superconductivity from doping symmetric mass generation insulators: application to La3Ni2O7 under pressure","authors":"Da-Chuan Lu, Miao Li, Zhao-Yi Zeng, Wanda Hou, Juven Wang, Fan Yang, Yi-Zhuang You","doi":"10.1038/s41535-026-00925-0","DOIUrl":"https://doi.org/10.1038/s41535-026-00925-0","url":null,"abstract":"We investigate the bilayer nickelates as a platform to realize the symmetric mass generation (SMG) insulator, a featureless Mott insulator that arises due to the Lieb-Schultz-Mattis (LSM) anomaly cancellation in bilayer spin-1/2 lattice systems. Through a single-orbital bilayer square lattice model involving intralayer hopping t and interlayer superexchange interaction J, we demonstrate the emergence of high-temperature superconductivity (SC) upon doping the SMG insulator. The SC phase features s-wave interlayer spin-singlet pairing and exhibits a crossover between the Bardeen-Cooper-Schrieffer (BCS) and Bose-Einstein condensation (BEC) limits by tuning the J/t ratio. We estimate the SC transition temperature Tc from both the weak and strong coupling limits at the mean-field level. Our findings offer insights into the experimentally observed decrease in Tc with pressure and the strange metal behavior above Tc. Additionally, we propose that both Ni (3{d}_{{z}^{2}}) and (3{d}_{{x}^{2}-{y}^{2}}) orbitals can exhibit superconductivity in La3Ni2O7 under pressure, but their Tc should vary in opposite ways under doping. This characteristic difference suggests a potential experimental pathway to identify which electronic orbital plays the principal role in the formation of superconductivity in this system.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"35 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148769284","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

Strain-control of electronic superlattice domains in CsV3Sb5 CsV3Sb5中电子超晶格域的应变控制

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-08 DOI: 10.1038/s41535-026-00933-0

E. Sadrollahi, J. Almeida Mendes, N. Stilkerich, A. K. Sharma, C. Shekhar, C. Felser, T. Ritschel, J. Geck

{"title":"Strain-control of electronic superlattice domains in CsV3Sb5","authors":"E. Sadrollahi, J. Almeida Mendes, N. Stilkerich, A. K. Sharma, C. Shekhar, C. Felser, T. Ritschel, J. Geck","doi":"10.1038/s41535-026-00933-0","DOIUrl":"https://doi.org/10.1038/s41535-026-00933-0","url":null,"abstract":"The kagome metals <italic>A</italic>V3Sb5 (A = K, Rb, Cs) provide a unique platform to investigate the physics of interacting electrons, a central challenge in condensed matter physics. A key obstacle in unraveling their correlated behavior is to determine which structural and electronic degrees of freedom are involved and how they couple. Here, we address this important issue with a novel approach, namely by exploring the strain dependence of electronic superlattices (SL) in CsV3Sb5. Using high-resolution x-ray diffraction, we track the detwinning of the 2 × 2 × 4 electronic crystal and uncover a gigantic strain response of its domains. We further show that the detwinned 2 × 2 × 4 phase exhibits an intrinsic double-<bold>q</bold> modulation and strong mode coupling. Density functional theory reveals that the structural 2 × 2 × 4 modulation couples strongly to the V 3<italic>d</italic>-orbitals, naturally explaining its pronounced strain response. In contrast, the 2 × 2 × 2 phase at lower temperatures remains essentially unaffected by small uniaxial strain. This dichotomy points to fundamental differences in the symmetry breaking and stabilization mechanisms of the two electronic orders. More specifically, our results provide evidence for the active role of orbital degrees of freedom, which can realize distinct, complex ordering patterns driven by competing interactions.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"26 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148687958","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

Revealing the microscopic origin of the magnetization plateau in Na3Ni2BiO6 揭示了Na3Ni2BiO6磁化平台的微观成因

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-08 DOI: 10.1038/s41535-026-00932-1

Amanda A. Konieczna, Marius Möller, P. Peter Stavropoulos, Roser Valentí

{"title":"Revealing the microscopic origin of the magnetization plateau in Na3Ni2BiO6","authors":"Amanda A. Konieczna, Marius Möller, P. Peter Stavropoulos, Roser Valentí","doi":"10.1038/s41535-026-00932-1","DOIUrl":"https://doi.org/10.1038/s41535-026-00932-1","url":null,"abstract":"Recent experimental studies of the spin-1 honeycomb antiferromagnet Na3Ni2BiO6 have revealed a pronounced one-third magnetization plateau under applied magnetic fields, highlighting the presence of strong magnetic frustration and anisotropy in this material. Such behavior has been attributed to substantial bond-dependent Kitaev interactions in combination with single-ion anisotropy, placing Na3Ni2BiO6 among honeycomb compounds of interest for unconventional magnetic phases. Motivated by these observations, we present a first-principles-based analysis of the magnetic interactions in Na3Ni2BiO6. By combining density-functional calculations with microscopic modeling, we extract the relevant exchange parameters and construct an effective spin model that qualitatively reproduces both the elastic neutron-scattering spectra and the magnetization curve. The model captures the experimentally observed zero-field zigzag magnetic order, and proposes a <italic>double-zigzag</italic> state at intermediate magnetic fields, realizing the one-third magnetization plateau in a simpler way than suggested in previous works. Crucially, we show that the one-third magnetization plateau does not require Kitaev interactions; instead, it arises from the interplay of strong out-of-plane single-ion anisotropy and competing ferromagnetic nearest-neighbor (<italic>J</italic>1) and antiferromagnetic third-neighbor (<italic>J</italic>3) Heisenberg couplings. These results establish a consistent microscopic description of Na3Ni2BiO6 and clarify the origin of its field-induced plateau phase from first principles.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"10 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148687996","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

Gate-dielectric stack engineering for high-mobility and low-noise SiMOS quantum devices 高迁移率和低噪声SiMOS量子器件的门-介电堆栈工程

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-06 DOI: 10.1038/s41535-026-00934-z

Md. Mamunur Rahman, Ensar Vahapoglu, Kok Wai Chan, Tuomo Tanttu, Ajit Dash, Jonathan Yue Huang, Steve Yianni, Venkatesh Chenniappan, Jesús D. Cifuentes, Fay E. Hudson, Christopher C. Escott, Yik Kheng Lee, Nard Dumoulin Stuyck, Arne Laucht, Andrea Morello, Andre Saraiva, Jared H. Cole, Andrew S. Dzurak, Wee Han Lim

{"title":"Gate-dielectric stack engineering for high-mobility and low-noise SiMOS quantum devices","authors":"Md. Mamunur Rahman, Ensar Vahapoglu, Kok Wai Chan, Tuomo Tanttu, Ajit Dash, Jonathan Yue Huang, Steve Yianni, Venkatesh Chenniappan, Jesús D. Cifuentes, Fay E. Hudson, Christopher C. Escott, Yik Kheng Lee, Nard Dumoulin Stuyck, Arne Laucht, Andrea Morello, Andre Saraiva, Jared H. Cole, Andrew S. Dzurak, Wee Han Lim","doi":"10.1038/s41535-026-00934-z","DOIUrl":"https://doi.org/10.1038/s41535-026-00934-z","url":null,"abstract":"We systematically investigate the interplay between materials engineering, quantum transport, and low-frequency charge noise in silicon metal-oxide-semiconductor (SiMOS) quantum devices. By combining Hall-bar transport measurements with charge-noise spectroscopy of gate-defined quantum dots, we identify correlations between gate-stack design, carrier mobility, and electrostatic noise, providing an experimental case study of material and process dependencies relevant to low-noise, high-mobility operation. Hall-bar studies show that varying the oxidant (H2O or D2O) during ALD Al2O3 growth has very little influence on mobility, whereas increasing the Al2O3 deposition temperature from 200 °C to 300 °C yields a modest improvement. Devices incorporating HfO2 exhibit enhanced carrier mobility, possibly due to defect passivation associated with aluminum diffusion into the dielectric from the gate metal. In contrast, gate-metal selection strongly influences transport properties, with TiPd-gated devices exhibiting substantially lower mobility than their Al-gated counterparts. Charge-noise measurements further reveal a clear correlation between mobility and noise performance, with lower-mobility devices generally exhibiting higher charge noise, while the poly-Si-gated CMOS-foundry device achieves the lowest noise level. Finally, dual-feedback dot-sensor stability mapping demonstrates enhanced charge stability in devices with the gate stacks studied here, underscoring their promise for scalable, high-fidelity silicon spin-qubit platforms.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"9 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148693514","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

Robust field-free superconducting diode effect in FeTe0.55Se0.45 FeTe0.55Se0.45中鲁棒无场超导二极管效应

IF 5.7 1区物理与天体物理

npj Quantum Materials Pub Date : 2026-08-02 DOI: 10.1038/s41535-026-00930-3

Peng Dong, Jinghui Wang, Yanjiang Wang, Jianjun Xiao, Xiang Zhou, Hui Xing, Kenji Watanabe, Takashi Taniguchi, Yueshen Wu, Yulin Chen, Jinsheng Wen, Jun Li

{"title":"Robust field-free superconducting diode effect in FeTe0.55Se0.45","authors":"Peng Dong, Jinghui Wang, Yanjiang Wang, Jianjun Xiao, Xiang Zhou, Hui Xing, Kenji Watanabe, Takashi Taniguchi, Yueshen Wu, Yulin Chen, Jinsheng Wen, Jun Li","doi":"10.1038/s41535-026-00930-3","DOIUrl":"https://doi.org/10.1038/s41535-026-00930-3","url":null,"abstract":"The superconducting diode effect (SDE), a nonreciprocal phenomenon where the critical supercurrent differs depending on the direction of current flow, is a promising foundation for superconducting logic and memory. Realizing its full potential requires a diode that operates without an applied magnetic field, which generally requires the breaking of both time-reversal and inversion symmetries in the superconducting system. Zero-field SDEs are often observed in heterostructures but remain rare in single materials. Here, we report the observation of a robust, field-free SDE in thin flakes of FeTe0.55Se0.45. A sensitive probe of nonreciprocal transport is the emergence of a pronounced second harmonic response near the superconducting transition under zero applied field, with an amplitude comparable to the standard first harmonic signal. The SDE persists at zero field and maintains its polarity under both large positive and negative magnetic fields, exhibiting an even-in-field symmetry that distinguishes it from mechanisms based on finite-momentum pairing or magnetochiral anisotropy. We systematically rule out alternative origins, including device geometry, thermal gradients, chiral domains, and extrinsic magnetic order. Instead, our analysis indicates that local strain/polarization-induced symmetry breaking is a primary factor in generating and enhancing the effect. These results identify iron-based high-temperature superconducting platforms as highly promising candidates for the field-free superconducting diode effect, benefiting from their coexistence of strong intrinsic disorder and superconductivity in a structurally simple form.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"360 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148693429","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