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Violation of emergent rotational symmetry in the hexagonal Kagome superconductor CsV
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Article
| Open AccessAnderson critical metal phase in trivial states protected by average magnetic crystalline symmetry
The authors identify a novel delocalization mechanism for topologically trivial obstructed insulators. In transitioning from two topologically trivial states, where one would expect Anderson’s localization to take place, a delocalized ‘critical metal phase’ appears.
- Fa-Jie Wang
- , Zhen-Yu Xiao
- & Zhi-Da Song
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Article
| Open AccessNonlinear optical diode effect in a magnetic Weyl semimetal
Here the authors demonstrate a broadband nonlinear optical diode effect and its electric control in the magnetic Weyl semimetal CeAlSi. Their findings advance ongoing research to identify novel optical phenomena in topological materials.
- Christian Tzschaschel
- , Jian-Xiang Qiu
- & Su-Yang Xu
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Article
| Open AccessHidden non-collinear spin-order induced topological surface states
Several recent experimental studies have found disconnected Fermi surface arcs emerging below the Neel temperature in several rare-earth mono-pnictides. While these electronic states have been attributed to a non-collinear antiferromagnetic order, experimental evidence of this has been lacking. Here Huang et al demonstrate the emergence of non-collinear antiferromagnetic order using spin-polarized scanning tunnelling microscopy.
- Zengle Huang
- , Hemian Yi
- & Weida Wu
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Article
| Open AccessObservation of Kekulé vortices around hydrogen adatoms in graphene
Kekulé vortices in hexagonal lattices can host fractionalized charges at zero magnetic field, but have remained out of experimental reach. Here, the authors report a Kekulé vortex in the local density states of graphene around a chemisorbed hydrogen adatom.
- Yifei Guan
- , Clement Dutreix
- & Vincent T. Renard
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Article
| Open AccessMagnetic field filtering of the boundary supercurrent in unconventional metal NiTe2-based Josephson junctions
The authors study Josephson junctions where the weak link is a NiTe2 flake. They find that in-plane magnetic field in a particular direction causes the supercurrent to concentrate in the edges of the flake, excluding the bulk. They further argue that the supercurrent is carried by higher-order hinge states.
- Tian Le
- , Ruihan Zhang
- & Fanming Qu
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Article
| Open AccessReversible non-volatile electronic switching in a near-room-temperature van der Waals ferromagnet
The controlled manipulation of the topological phases of electronic materials is a central goal of modern condensed matter research. Here, the authors demonstrate controllable switching between two distinct topological phases in a layered ferromagnet via thermal cycling.
- Han Wu
- , Lei Chen
- & Ming Yi
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Article
| Open AccessTopological minibands and interaction driven quantum anomalous Hall state in topological insulator based moiré heterostructures
Moiré patterns have been experimentally observed in heterostructures comprised of topological insulator films. Here, the authors propose that topological insulator-based moiré heterostructures could be a host of isolated topologically non-trivial moiré minibands for the study of the interplay between topology and correlation.
- Kaijie Yang
- , Zian Xu
- & Chao-Xing Liu
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Article
| Open AccessTwisted photonic Weyl meta-crystals and aperiodic Fermi arc scattering
Fermi arcs show unpredictable diffraction features resulting from their long-range scattering order in aperiodic systems. Here, authors continuously twist a bi-block Weyl meta-crystal and experimentally observe the twisted Fermi arc reconstruction.
- Hanyu Wang
- , Wei Xu
- & Biao Yang
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Article
| Open AccessDislocation Majorana bound states in iron-based superconductors
The authors propose that screw or edge dislocations can trap Majorana zero modes in the absence of an external magnetic field. They predict that the Majoranas will appear as second-order topological modes on the four corners of an embedded 2D subsystem defined by the cutting plane of the dislocation.
- Lun-Hui Hu
- & Rui-Xing Zhang
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Article
| Open AccessAtomically precise engineering of spin–orbit polarons in a kagome magnetic Weyl semimetal
Defect engineering in topological materials is a frontier that promises tunable physical properties with rich applications. Here, the authors demonstrate the atomically precise engineering of vacancies in a topological semimetal, which locally tunes the magnetic properties.
- Hui Chen
- , Yuqing Xing
- & Hong-Jun Gao
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Article
| Open AccessRevealing Fermi surface evolution and Berry curvature in an ideal type-II Weyl semimetal
The authors study the field-induced ferromagnetic state of MnBi2-xSbxTe4 by quantum oscillations and high-field Hall effect measurements. They confirm a single pair of type-II Weyl nodes, the long-sought “ideal” Weyl semimetal.
- Qianni Jiang
- , Johanna C. Palmstrom
- & Jiun-Haw Chu
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Article
| Open AccessAnomalous and Chern topological waves in hyperbolic networks
Here the authors experimentally demonstrate the anomalous and Chern topological phases in a hyperbolic non-reciprocal scattering network, establishing unidirectional channels to induce new and exciting wave transport properties in curved spaces.
- Qiaolu Chen
- , Zhe Zhang
- & Romain Fleury
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Article
| Open AccessThe discovery of three-dimensional Van Hove singularity
Van Hove singularities (VHS) are believed to exist in one and two dimensions, but rarely found in three dimensions (3D). Here the authors report the discovery of 3D VHS in a topological magnet EuCd2As2 by magneto-infrared spectroscopy.
- Wenbin Wu
- , Zeping Shi
- & Xiang Yuan
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Article
| Open AccessObservation of vortex-string chiral modes in metamaterials
Vortex string, hypothetical topological defects in cosmology, are predicted to support massless chiral modes. The authors successfully mimicked vortex-string physics in a metamaterial system and experimentally observed the chiral modes within it.
- Jingwen Ma
- , Ding Jia
- & Xiang Zhang
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| Open AccessThree-dimensional flat Landau levels in an inhomogeneous acoustic crystal
Artificial magnetic fields have been meticulously engineered in a 3D acoustic crystal, facilitating the creation of 3D flat bands through Landau quantization of quasiparticles arising from nodal-ring band degeneracies.
- Zheyu Cheng
- , Yi-Jun Guan
- & Baile Zhang
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Perspective
| Open AccessQuantum many-body simulations on digital quantum computers: State-of-the-art and future challenges
Digital quantum simulations of quantum many-body systems have emerged as one of the most promising applications of near-term quantum computing. This Perspective article provides an overview and an outlook on future developments in this field.
- Benedikt Fauseweh
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Article
| Open AccessQuantifying the photocurrent fluctuation in quantum materials by shot noise
The bulk photovoltaic effect and DC photocurrent generation can be used to detect topology and geometry in non-centrosymmetric quantum materials. Here, the authors theoretically propose the detection of DC shot noise as a diagnostic tool for the characterization of the band quantum geometry under relaxed symmetry conditions.
- Longjun Xiang
- , Hao Jin
- & Jian Wang
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Article
| Open AccessLight-induced switching between singlet and triplet superconducting states
S. Gassner et al. propose using light pulses to drive a centrosymmetric s-wave superconductor with strong spin-orbit coupling into a metastable triplet p-wave superconductor with non-trivial topology. The two superconducting orders must be closely competing in equilibrium and the light pulse must break a generalized, dynamic form of inversion symmetry.
- Steven Gassner
- , Clara S. Weber
- & Martin Claassen
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Article
| Open AccessHomochiral antiferromagnetic merons, antimerons and bimerons realized in synthetic antiferromagnets
Topological antiferromagnetic spin textures, including merons, antimerons, and bimerons, are demonstrated in synthetic antiferromagnets by three-dimensional vector imaging of the Néel order parameter and investigated by micromagnetic analysis.
- Mona Bhukta
- , Takaaki Dohi
- & Mathias Kläui
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Article
| Open AccessHyperbolic photonic topological insulators
Here the authors develop a coupled ring resonators platform for realizing topological states of matter with hyperbolic dispersion thus offering an approach to boost the efficiency of topological photonic devices.
- Lei Huang
- , Lu He
- & Xiangdong Zhang
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Article
| Open AccessMeasuring entanglement entropy and its topological signature for phononic systems
Entanglement entropy exhibits rich phenomenology connected to different kinds of phases in condensed matter. Here, the authors confirm some of these predictions by experimentally probing nonlocal correlations in 1D and 2D phononic crystal based on interconnected resonating acoustic cavities.
- Zhi-Kang Lin
- , Yao Zhou
- & Jian-Hua Jiang
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Article
| Open AccessChiral and flat-band magnetic quasiparticles in ferromagnetic and metallic kagome layers
S. X. M. Riberolles et al. study the kagome Chern insulator TbMn6Sn6 via inelastic neutron scattering. They observe signatures of chiral and flat-band magnons, which are highly localized in real space and strongly damped in the time domain.
- S. X. M. Riberolles
- , Tyler J. Slade
- & R. J. McQueeney
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Article
| Open AccessEvidence for Topological Protection Derived from Six-Flux Composite Fermions
Huang et al. study fractional quantum Hall (fQH) states in high-quality GaAs/AlGaAs samples. They report evidence for a fQH state at filling factor ν = 9/11, which they associate with the formation of six-flux composite fermions.
- Haoyun Huang
- , Waseem Hussain
- & G. A. Csáthy
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Article
| Open AccessRobust temporal adiabatic passage with perfect frequency conversion between detuned acoustic cavities
Phase matching is pivotal for realizing complete energy transfer for classical waves. Here, authors propose temporal quasi-phase matching method and realize robust and complete energy transfer between arbitrarily detuned acoustic cavities by combing the concept of stimulated Raman adiabatic passage.
- Zhao-Xian Chen
- , Yu-Gui Peng
- & Yan-Qing Lu
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Article
| Open AccessTunable positions of Weyl nodes via magnetism and pressure in the ferromagnetic Weyl semimetal CeAlSi
Topological semimetals with space-inversion and time-reversal symmetry breaking have attracted attention recently. Here, using a combination of experimental techniques and calculations, the authors demonstrate the tunability of the Weyl nodes via magnetism and pressure in the ferromagnetic Weyl semimetal CeAlSi.
- Erjian Cheng
- , Limin Yan
- & Bernd Büchner
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Article
| Open AccessNonlinear topological symmetry protection in a dissipative system
Applications of spontaneous symmetry breaking are hindered by unavoidable imperfections. Here, the authors reveal how a phase defect provides topological robustness to this process, enabling a bias free realization without fine tuning of parameters.
- Stéphane Coen
- , Bruno Garbin
- & Julien Fatome
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Article
| Open AccessResolving the topology of encircling multiple exceptional points
When multiple oscillators are tuned, degeneracies occur on a knot-shaped region in the space of tuning parameters. This knot influences how such systems can be tuned. Here, the authors reconcile two common means for visualizing this influence.
- Chitres Guria
- , Qi Zhong
- & Jack Gwynne Emmet Harris
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Article
| Open AccessObservation of giant room-temperature anisotropic magnetoresistance in the topological insulator β-Ag2Te
Achieving room-temperature high anisotropic magnetoresistance ratios is highly desirable for magnetic sensors. Here, the authors observe a high anisotropic magnetoresistance ratio of −39% and a giant planar Hall effect (520 μΩ·cm) at room temperature under 9 T in β-Ag2Te crystals grown by CVD.
- Wei Ai
- , Fuyang Chen
- & Jinxiong Wu
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Article
| Open AccessInteracting topological quantum chemistry in 2D with many-body real space invariants
While the classification of single-particle topological phases has been established, recent efforts have been made to extend it to interacting limit. Here the authors present a classification of interacting topological systems in 2D based on the generalization of real space invariants.
- Jonah Herzog-Arbeitman
- , B. Andrei Bernevig
- & Zhi-Da Song
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Article
| Open AccessNon-Abelian Floquet braiding and anomalous Dirac string phase in periodically driven systems
R.-J. Slager et al. extend the theory of multigap topology from static to non-equilibrium systems. They identify Floquet-induced non-Abelian braiding, resulting in a phase characterized by anomalous Euler class, a multi-gap topological invariant. They also find a gapped anomalous Dirac string phase. Both phases have no static counterparts and exhibit distinct boundary signatures.
- Robert-Jan Slager
- , Adrien Bouhon
- & F. Nur Ünal
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Article
| Open AccessSupercurrent mediated by helical edge modes in bilayer graphene
P. Rout et al. study Josephson junctions where the weak link is WSe2-encapsulated bilayer graphene, which features helical edge modes. They argue that the supercurrent channels along opposite edges of the weak link are coupled by a circulating helical mode.
- Prasanna Rout
- , Nikos Papadopoulos
- & Srijit Goswami
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Article
| Open AccessChirality manipulation of ultrafast phase switches in a correlated CDW-Weyl semimetal
The charge-density-wave Weyl semimetal (TaSe4)2I is a candidate for an axion insulator, however it may be obscured by polaron physics. Here, using ultrafast terahertz photocurrent spectroscopy, the authors realize phase switches from the polaronic state, to the charge density wave phase, and to the Weyl phase.
- Bing Cheng
- , Di Cheng
- & Jigang Wang
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Article
| Open AccessMagnon thermal Hall effect via emergent SU(3) flux on the antiferromagnetic skyrmion lattice
Strongly correlated and topological phases of matter can be often described using the tools of quantum field theory. Here the authors report the thermal Hall effect in the antiferromagnetic skyrmion lattice of MnSc2S4, revealing transport features that can be attributed to an emergent SU(3) gauge field.
- Hikaru Takeda
- , Masataka Kawano
- & Chisa Hotta
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Article
| Open AccessSpin-resolved topology and partial axion angles in three-dimensional insulators
3D higher-order topological insulators (HOTIs) exhibit 1D hinge states depending on extrinsic sample details, while intrinsic features of HOTIs remain unknown. Here, K.S. Lin et al. introduce the framework of spin-resolved topology to show that helical HOTIs can realize a doubled axion insulator phase with nontrivial partial axion angles.
- Kuan-Sen Lin
- , Giandomenico Palumbo
- & Barry Bradlyn
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Article
| Open AccessMotion and teleportation of polar bubbles in low-dimensional ferroelectrics
Nanoscale ferroelectric domains called electric bubbles are shown to behave as dynamical particles. Using atomistic simulations and experiments, the authors reveal a bubble liquid phase and demonstrate teleportation-like displacements of single bubbles.
- S. Prokhorenko
- , Y. Nahas
- & L. Bellaiche
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Article
| Open AccessControllable strain-driven topological phase transition and dominant surface-state transport in HfTe5
Manipulating the topological phases of quantum materials is necessary to fully leverage their potential for future electronics. Here, the authors experimentally demonstrate the controllable transition from a weak to a strong topological insulator phase through the in-situ application of high strain.
- Jinyu Liu
- , Yinong Zhou
- & Luis A. Jauregui
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Article
| Open AccessThermal Hall effects due to topological spin fluctuations in YMnO3
The thermal Hall effect has been reported in several materials, but it is not expected in triangular lattice systems due to chirality cancellation. Kim et al. report the thermal Hall effect attributed to topological spin fluctuations in the supposedly paramagnetic phase of YMnO3 with a trimerized triangular lattice.
- Ha-Leem Kim
- , Takuma Saito
- & Je-Geun Park
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Article
| Open AccessTransition to the Haldane phase driven by electron-electron correlations
At the microscopic level, the localized spins arise due to the electron-electron interactions. Here, the authors show how a topological phase of the Haldane spin chain emerges in a two-orbital Hubbard model with increasing interaction strength.
- A. Jażdżewska
- , M. Mierzejewski
- & J. Herbrych
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| Open AccessManipulation of fractionalized charge in the metastable topologically entangled state of a doped Wigner crystal
The metastable state with a complex domain structure in 1T-TaS2 has been intensively studied. Using a multi-tip scanning tunnelling microscope, Mraz et al. reveal the microscopic dynamics of the current-pulse-induced metastable state and interpret it in terms of transport in a doped Wigner crystal lattice.
- Anze Mraz
- , Michele Diego
- & Dragan Mihailovic
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Article
| Open AccessOrbital topological edge states and phase transitions in one-dimensional acoustic resonator chains
The researchers demonstrate orbital-dependent sound-matter interactions in acoustic systems. They unveil duality symmetry and topological phase transitions beyond the conventional SSH model expanding the fundamental understanding of sound-matter interaction.
- Feng Gao
- , Xiao Xiang
- & Andrea Alù
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Article
| Open AccessTopological electronic structure and spin texture of quasi-one-dimensional higher-order topological insulator Bi4Br4
W. X. Zhao et al. study the higher-order topological insulator candidate Bi4Br4 by angle-resolved photoemission spectroscopy (ARPES) and ab-initio calculation. They provide strong evidence for the higher-order topological insulator phase, including a signature of the hinge states inside the (100) surface gap.
- Wenxuan Zhao
- , Ming Yang
- & Lexian Yang
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Article
| Open AccessA robust and tunable Luttinger liquid in correlated edge of transition-metal second-order topological insulator Ta2Pd3Te5
The interplay of electronic correlations and topology has been a forefront topic in condensed matter physics. Wang et al. present evidence of a correlated topological edge state supporting the Luttinger liquid behaviour in the candidate quadrupole topological insulator Ta2Pd3Te5.
- Anqi Wang
- , Yupeng Li
- & Jie Shen
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Article
| Open AccessAxion insulator state in hundred-nanometer-thick magnetic topological insulator sandwich heterostructures
A zero Hall conductance plateau has been taken as evidence of the axion insulator state in magnetically doped topological insulator heterostructures, but it can also originate from surface state hybridization. Here the authors establish such a state in a ~106 nm thick sample, where hybridization is negligible.
- Deyi Zhuo
- , Zi-Jie Yan
- & Cui-Zu Chang
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Article
| Open AccessMott insulators with boundary zeros
Topological classification of interacting electronic states has emerged as an important topic recently. Wagner at al. show that the momentum structure of the zeros of the electron Green’s function can be used to identify a topological Mott insulator phase, similarly to the single-particle dispersion.
- N. Wagner
- , L. Crippa
- & G. Sangiovanni
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Article
| Open AccessSimultaneous and independent topological control of identical microparticles in non-periodic energy landscapes
External fields can control the motion of colloidal particles inducing different trajectories depending on for instance the particle size. The authors here use nonperiodic energy landscapes and topological protection to transport a collection of identical colloidal particles simultaneously and independently.
- Nico C. X. Stuhlmüller
- , Farzaneh Farrokhzad
- & Daniel de las Heras
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Article
| Open AccessAntiferromagnetic topological insulator with selectively gapped Dirac cones
Antiferromagnetic topological materials have attracted attention recently due to their unique quantum properties and application potential. Here the authors establish an antiferromagnetic topological insulator in NdBi and demonstrate gapped and gapless surface states in two different magnetic domains.
- A. Honma
- , D. Takane
- & T. Sato
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Article
| Open AccessBulk-local-density-of-state correspondence in topological insulators
Current approaches to distinguish topological phases from topologically-trivial phases have limited general applicability. Here, in a photonic-crystal context, the authors demonstrate that in trivial structures the bulk local density of states (LDOS) extends all the way to the edges and corners, while in topological structures the bulk LDOS actually avoids the edges and corners.
- Biye Xie
- , Renwen Huang
- & Shuang Zhang
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Article
| Open AccessEmergence of Weyl fermions by ferrimagnetism in a noncentrosymmetric magnetic Weyl semimetal
A Weyl semimetal formally requires either broken time reversal symmetry or inversion symmetry. One class of Weyl semimetals-the crystal family of NdAlSi-exhibits both. Here, Li et al perform angle-resolved photoemission spectroscopy measurements on NdAlSi, and observe the formation of an additional Weyl fermion as the material becomes ferrimagnetic.
- Cong Li
- , Jianfeng Zhang
- & Oscar Tjernberg
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Article
| Open AccessDirac-fermion-assisted interfacial superconductivity in epitaxial topological-insulator/iron-chalcogenide heterostructures
The authors study (Bi,Sb)2Te3/FeTe bilayers, which feature emergent superconductivity at the interface with Tc ~ 12 K. Through angle-resolved photoemission spectroscopy and electrical transport measurements, they argue that the Dirac-fermion-mediated Ruderman-Kittel-Kasuya-Yosida-type interaction weakens antiferromagnetic order in FeTe layer, allowing for superconductivity.
- Hemian Yi
- , Lun-Hui Hu
- & Cui-Zu Chang