Topological matter articles within Nature

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• Article | 04 August 2021

  Quantized nonlinear Thouless pumping

  Nonlinearity is shown to induce quantized topological transport via soliton motion; specifically, we demonstrate nonlinear Thouless pumping of photons in waveguide arrays with a non-uniformly occupied energy band.

  • Marius Jürgensen
  • , Sebabrata Mukherjee
  •  & Mikael C. Rechtsman

• Article | 21 July 2021

  Layer Hall effect in a 2D topological axion antiferromagnet

  A new type of Hall effect—the layer Hall effect—is produced in a 2D antiferromagnet that does not exhibit any net magnetization.

  • Anyuan Gao
  • , Yu-Fei Liu
  •  & Su-Yang Xu

• Article
  16 June 2021 | Open Access

  Symmetry-enforced topological nodal planes at the Fermi surface of a chiral magnet

  Measurements on a chiral magnet show that non-symmorphic symmetries enforce topological crossings exactly at the Fermi level in certain materials; these crossings can be controlled by an applied magnetic field.

  • Marc A. Wilde
  • , Matthias Dodenhöft
  •  & Christian Pfleiderer

• Article | 19 May 2021

  Tunable non-integer high-harmonic generation in a topological insulator

  High-harmonic generation from the Dirac-like surface state of a topological insulator is separated from bulk contributions and continuously tuned by the carrier-envelope phase of the driving lightwave.

  • C. P. Schmid
  • , L. Weigl
  •  & R. Huber

• Article | 14 April 2021

  Subterahertz collective dynamics of polar vortices

  A dynamical study shows that vortices of electrical polarization have higher frequencies and smaller size than their magnetic counterparts, properties that are promising for electric-field-driven data processing.

  • Qian Li
  • , Vladimir A. Stoica
  •  & Haidan Wen

• Article | 07 April 2021

  Entropic evidence for a Pomeranchuk effect in magic-angle graphene

  Magic-angle graphene is found to have an exotic phase transition where, on heating, entropy is transferred from motional to magnetic degrees of freedom, analogously to the Pomeranchuk effect in ³He.

  • Asaf Rozen
  • , Jeong Min Park
  •  & Shahal Ilani

• Article | 20 January 2021

  Trapped fractional charges at bulk defects in topological insulators

  It is experimentally shown that crystallographic defects may trap fractional charges, as well as topological states, in the bulk of topological crystalline insulators.

  • Christopher W. Peterson
  • , Tianhe Li
  •  & Gaurav Bahl

• Article | 20 January 2021

  Bulk–disclination correspondence in topological crystalline insulators

  It is experimentally shown that topological states exist at crystallographic defects in the bulk and that disclination defects trap fractional charges characteristic of topological crystalline insulators.

  • Yang Liu
  • , Shuwai Leung
  •  & Jian-Hua Jiang

• Article | 04 January 2021

  Landau quantization and highly mobile fermions in an insulator

  Pronounced quantum oscillations in magnetoresistance, a phenomenon that was only expected in metals with highly mobile carriers, are observed in the strongly insulating state of two-dimensional WTe₂.

  • Pengjie Wang
  • , Guo Yu
  •  & Sanfeng Wu

• Article | 16 December 2020

  Tuning the Chern number in quantum anomalous Hall insulators

  The number of edge channels in quantum anomalous Hall insulators is controlled by varying either the magnetic dopant concentration or the interior spacer layer thickness, yielding Chern numbers up to 5.

  • Yi-Fan Zhao
  • , Ruoxi Zhang
  •  & Cui-Zu Chang

• Article | 16 December 2020

  Topological superconductivity in a van der Waals heterostructure

  A van der Waals structure based on a two-dimensional magnet and layered superconductor offers a potential system in which topological superconductivity could be easily tuned and integrated into devices.

  • Shawulienu Kezilebieke
  • , Md Nurul Huda
  •  & Peter Liljeroth

• Article | 14 December 2020

  Strongly correlated Chern insulators in magic-angle twisted bilayer graphene

  Strong electron–electron interactions in magic-angle twisted bilayer graphene can fundamentally change the topology of the system’s flat bands, producing a hierarchy of strongly correlated topological insulators in modest magnetic fields.

  • Kevin P. Nuckolls
  • , Myungchul Oh
  •  & Ali Yazdani

• Article | 23 November 2020

  Electrical switching of magnetic order in an orbital Chern insulator

  Non-volatile electrical switching of magnetic order in an orbital Chern insulator is experimentally demonstrated using a moiré heterostructure and analysis shows that the effect is driven by topological edge states.

  • H. Polshyn
  • , J. Zhu
  •  & A. F. Young

• Article | 28 October 2020

  High-throughput calculations of magnetic topological materials

  High-throughput calculations are performed to predict approximately 130 magnetic topological materials, with complete electronic structure calculations and topological phase diagrams.

  • Yuanfeng Xu
  • , Luis Elcoro
  •  & B. Andrei Bernevig

• Article | 05 August 2020

  Quantum distance and anomalous Landau levels of flat bands

  The semiclassical quantization rule breaks down for a class of dispersionless flat bands, and their anomalous Landau level spectrum is characterized by their Hilbert–Schmidt quantum distance.

  • Jun-Won Rhim
  • , Kyoo Kim
  •  & Bohm-Jung Yang

• Article | 22 July 2020

  Quantum-limit Chern topological magnetism in TbMn₆Sn₆

  Scanning tunnelling microscopy is used to reveal a new topological kagome magnet with an intrinsic Chern quantum phase, which shows a distinct Landau fan structure with a large Chern gap.

  • Jia-Xin Yin
  • , Wenlong Ma
  •  & M. Zahid Hasan

• Article | 03 June 2020

  Observation of Laughlin states made of light

  Pairs of photons in the Laughlin state are created by mimicking a fractional quantum Hall system using the synthetic magnetic field induced by a twisted optical cavity and Rydberg-mediated polariton interactions.

  • Logan W. Clark
  • , Nathan Schine
  •  & Jonathan Simon

• Article | 27 April 2020

  Iron-based binary ferromagnets for transverse thermoelectric conversion

  Aluminium- and gallium-doped iron compounds show a large anomalous Nernst effect owing to a topological electronic structure, and their films are potentially suitable for designing low-cost, flexible microelectronic thermoelectric generators.

  • Akito Sakai
  • , Susumu Minami
  •  & Satoru Nakatsuji

• Article | 20 April 2020

  Electrical manipulation of a topological antiferromagnetic state

  Room-temperature electrical switching of a topological antiferromagnetic state in polycrystalline Mn₃Sn thin films is demonstrated using the same protocol as that used for conventional ferromagnetic metals.

  • Hanshen Tsai
  • , Tomoya Higo
  •  & Satoru Nakatsuji

• Article | 25 March 2020

  Chiral superconductivity in heavy-fermion metal UTe₂

  Scanning tunnelling microscopy and spectroscopy measurements show chiral edge states inside the superconducting gap of the heavy-fermion superconductor UTe₂, indicating the presence of chiral spin-triplet superconductivity.

  • Lin Jiao
  • , Sean Howard
  •  & Vidya Madhavan

• Article | 04 March 2020

  Tunable correlated Chern insulator and ferromagnetism in a moiré superlattice

  A topological Chern insulating state is reported to emerge from strong correlations in flat moiré bands in a graphene superlattice and by applying a vertical electric field the Chern number is switched.

  • Guorui Chen
  • , Aaron L. Sharpe
  •  & Feng Wang

• Article | 19 February 2020

  Measurement of the quantum geometric tensor and of the anomalous Hall drift

  Direct measurement of the Berry curvature and the quantum metric of photonic modes in a high-finesse planar microcavity is achieved, enabling quantitative prediction of the independently measured anomalous Hall drift.

  • A. Gianfrate
  • , O. Bleu
  •  & G. Malpuech

• Article | 01 January 2020

  Inverse transition of labyrinthine domain patterns in ferroelectric thin films

  The labyrinthine domain patterns formed in ultrathin films of ferroelectric oxides by subcritical quenching undergo an inverse phase transition to the less-symmetric parallel-stripe domain structure upon increasing temperature.

  • Y. Nahas
  • , S. Prokhorenko
  •  & L. Bellaiche

• Article | 18 December 2019

  Large magnetic gap at the Dirac point in Bi₂Te₃/MnBi₂Te₄ heterostructures

  In theory, the anomalous quantum Hall effect is observed in edge channels of topological insulators when there is a magnetic energy gap at the Dirac point; this gap has now been observed by low-temperature photoelectron spectroscopy in Mn-doped Bi₂Te₃.

  • E. D. L. Rienks
  • , S. Wimmer
  •  & G. Springholz

• Article | 18 December 2019

  Prediction and observation of an antiferromagnetic topological insulator

  An intrinsic antiferromagnetic topological insulator, MnBi₂Te₄, is theoretically predicted and then realized experimentally, with implications for the study of exotic quantum phenomena.

  • M. M. Otrokov
  • , I. I. Klimovskikh
  •  & E. V. Chulkov

• Article | 30 October 2019

  Superconductors, orbital magnets and correlated states in magic-angle bilayer graphene

  The fabrication of magic-angle twisted bilayer graphene devices with highly uniform twist angles enables the observation of new superconducting domes, orbital magnets and Chern insulating states.

  • Xiaobo Lu
  • , Petr Stepanov
  •  & Dmitri K. Efetov

• Article | 21 October 2019

  Imaging work and dissipation in the quantum Hall state in graphene

  Imaging studies show that topological protection in the quantum Hall state in graphene is undermined by edge reconstruction with a dissipation mechanism that comprises two distinct and spatially separated processes—work generation and entropy generation.

  • A. Marguerite
  • , J. Birkbeck
  •  & E. Zeldov

• Article | 07 October 2019

  Axionic charge-density wave in the Weyl semimetal (TaSe₄)₂I

  In the charge-density-wave Weyl semimetal (TaSe₄)₂I, an axion is observed and identified as a sliding mode in the charge-density-wave phase characterized by anomalous magnetoelectric transport effects.

  • J. Gooth
  • , B. Bradlyn
  •  & C. Felser

• Letter | 30 September 2019

  Measuring the Berry phase of graphene from wavefront dislocations in Friedel oscillations

  The Berry phase of graphene is measured in the absence of an applied magnetic field by observing dislocations in the Friedel oscillations formed at a hydrogen atom adsorbed on graphene.

  • C. Dutreix
  • , H. González-Herrero
  •  & V. T. Renard

• Letter | 19 June 2019

  Perfect Andreev reflection due to the Klein paradox in a topological superconducting state

  Perfect transmission of electrons through a finite potential barrier between a normal metal and a topological superconducting state is demonstrated, as evidenced by an exact doubling of conductance in point contact measurements.

  • Seunghun Lee
  • , Valentin Stanev
  •  & Ichiro Takeuchi

• Letter | 12 June 2019

  Spin–orbit-driven band inversion in bilayer graphene by the van der Waals proximity effect

  By enhancing the spin–orbit coupling in bilayer graphene using the proximity effect in a van der Waals heterostructure, band inversion occurs and an incompressible, gapped phase is produced.

  • J. O. Island
  • , X. Cui
  •  & A. F. Young

• Letter | 24 April 2019

  Topological superconductivity in a phase-controlled Josephson junction

  Majorana bound states are created in a two-dimensional architecture by confining Majorana channels within a planar Josephson junction, using the phase difference across the junction and an in-plane magnetic field.

  • Hechen Ren
  • , Falko Pientka
  •  & Amir Yacoby

• Letter | 24 April 2019

  Evidence of topological superconductivity in planar Josephson junctions

  Evidence is found for phase-tunable Majorana zero modes in scalable two-dimensional Josephson junctions produced by top-down fabrication.

  • Antonio Fornieri
  • , Alexander M. Whiticar
  •  & Fabrizio Nichele

• Letter | 20 March 2019

  Observation of unconventional chiral fermions with long Fermi arcs in CoSi

  Angle-resolved photoemission spectroscopy measurements in CoSi reveal the presence of unconventional chiral fermions near the Fermi level, with giant surface Fermi arcs and one pair of well separated chiral nodes.

  • Zhicheng Rao
  • , Hang Li
  •  & Hong Ding

• Letter | 20 March 2019

  Topological chiral crystals with helicoid-arc quantum states

  Angle-resolved photoemission spectroscopy measurements reveal that CoSi and RhSi are nearly ideal topological conductors, with structural chirality and surface helicoid arcs of topological charge ±2 arising from bulk multifold chiral states.

  • Daniel S. Sanchez
  • , Ilya Belopolski
  •  & M. Zahid Hasan

• Article | 27 February 2019

  Comprehensive search for topological materials using symmetry indicators

  An algorithm based on symmetry indicators is used to search a crystallographic database and finds thousands of candidate topological materials, which could be exploited in next-generation electronic devices.

  • Feng Tang
  • , Hoi Chun Po
  •  & Xiangang Wan

• Article | 27 February 2019

  Catalogue of topological electronic materials

  Topological materials are thought to be scarce, but an algorithm that diagnoses nontrivial topology in nonmagnetic materials finds the opposite: more than 30 per cent of the 26,688 materials studied are topological.

  • Tiantian Zhang
  • , Yi Jiang
  •  & Chen Fang

• Article | 27 February 2019

  A complete catalogue of high-quality topological materials

  Topological quantum chemistry and newly developed codes are used to analyse and compute the topological properties of materials in a large crystal database and to identify new topological phases, finding that more than 27 per cent of all materials in nature are topological.

  • M. G. Vergniory
  • , L. Elcoro
  •  & Zhijun Wang

• Letter | 11 February 2019

  A weak topological insulator state in quasi-one-dimensional bismuth iodide

  Angle-resolved photoemission spectroscopy is used to characterize the surface states of bismuth iodide, providing experimental evidence of a weak topological insulator state that had previously been only theoretically predicted.

  • Ryo Noguchi
  • , T. Takahashi
  •  & Takeshi Kondo

• Letter | 06 February 2019

  Interacting multi-channel topological boundary modes in a quantum Hall valley system

  Scanning tunnelling microscopy shows that 1D channels between quantum Hall states with different valley polarization are metallic or insulating depending on constraints imposed on electron–electron interaction by valley flavour.

  • Mallika T. Randeria
  • , Kartiek Agarwal
  •  & Ali Yazdani

• Letter | 09 January 2019

  Realization of a three-dimensional photonic topological insulator

  A three-dimensional photonic topological insulator is presented, made of split-ring resonators with strong magneto-electric coupling, which has an extremely wide topological bandgap, forbidding light propagation.

  • Yihao Yang
  • , Zhen Gao
  •  & Hongsheng Chen

• Article | 09 January 2019

  Electromagnetic and gravitational responses of photonic Landau levels

  Probing the local response of an integer quantum Hall system enables three different measures of its topology to be explored.

  • Nathan Schine
  • , Michelle Chalupnik
  •  & Jonathan Simon

• Letter | 17 December 2018

  Quantum Hall effect based on Weyl orbits in Cd₃As₂

  Quantized conductivity is observed along a Weyl orbit in wedge-shaped samples of the topological semimetal Cd₃As₂, providing evidence of the quantum Hall effect in three dimensions.

  • Cheng Zhang
  • , Yi Zhang
  •  & Faxian Xiu

• Letter | 12 December 2018

  Experimental realization of on-chip topological nanoelectromechanical metamaterials

  Topological nanoelectromechanical metamaterials are realized at the micrometre scale, using silicon nitride nanomembranes, opening the way for on-chip integrated acoustic components in high-frequency signal-processing applications.

  • Jinwoong Cha
  • , Kun Woo Kim
  •  & Chiara Daraio

• Letter | 10 December 2018

  Electric-field-tuned topological phase transition in ultrathin Na₃Bi

  An electrically controlled phase transition from topological insulator to conventional insulator in ultrathin films of the topological Dirac semimetal, Na₃Bi.

  • James L. Collins
  • , Anton Tadich
  •  & Mark T. Edmonds

• Letter | 05 December 2018

  Transformation between meron and skyrmion topological spin textures in a chiral magnet

  A magnetically induced two-dimensional square lattice of merons and antimerons is observed in real space, along with its transformation into a hexagonal lattice of skyrmions at room temperature.

  • X. Z. Yu
  • , W. Koshibae
  •  & Y. Tokura

• Letter | 08 October 2018

  Exciton-polariton topological insulator

  A part-light, part-matter exciton-polariton topological insulator is created in an array of semiconductor microcavities.

  • S. Klembt
  • , T. H. Harder
  •  & S. Höfling

• Letter | 26 September 2018

  Subcycle observation of lightwave-driven Dirac currents in a topological surface band

  Time- and angle-resolved photoemission spectroscopy reveals how Dirac fermions in the band structure of the topological surface state of Bi₂Te₃ are accelerated by the carrier wave of a terahertz-frequency light pulse.

  • J. Reimann
  • , S. Schlauderer
  •  & R. Huber

• Letter | 12 September 2018

  Giant and anisotropic many-body spin–orbit tunability in a strongly correlated kagome magnet

  The topological magnet Fe₃Sn₂ exhibits a giant nematic energy shift of a many-body electronic state, demonstrating anisotropic spin–orbit tunability.

  • Jia-Xin Yin
  • , Songtian S. Zhang
  •  & M. Zahid Hasan

• Letter | 22 August 2018

  Photonic topological Anderson insulators

  A counter-intuitive state—known as a topological Anderson insulator—in which strong disorder leads to the formation of topologically protected rather than trivial states is realized in a photonic system.

  • Simon Stützer
  • , Yonatan Plotnik
  •  & Alexander Szameit