Non-Hermitian higher-order topological insulators enabled by altermagnet engineering

Abstract

We show that proximity to an altermagnet provides an efficient route to engineering non-Hermitian higher-order topological phases. The proximity-induced altermagnetic order gaps the edge states of a topological insulator, thereby driving a transition from a first-order to a second-order topological phase. When combined with nonreciprocal hopping, the system exhibits both the non-Hermitian skin effect and a hybrid skin-topological effect, whereby first-order edge states and second-order corner states accumulate at selected corners of the lattice. We demonstrate that the spectral winding number of the edge states under cylindrical geometry dictates this corner localization and can be reversed by tuning the altermagnetic order. Consequently, both edge and corner states become directionally controllable. Our results establish altermagnets as a versatile platform for realizing and tuning skin-topological phenomena in non-Hermitian higher-order topological systems.

7 page,4 figures

References in corpus (87)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Real Spectra in Non-Hermitian Hamiltonians Having PT Symmetry
• Edge states and topological invariants of non-Hermitian systems
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Exceptional Topology of Non-Hermitian Systems
• Non-Hermitian Physics
• Biorthogonal Bulk-Boundary Correspondence in Non-Hermitian Systems
• Topological Origin of Non-Hermitian Skin Effects
• Topological Band Theory for Non-Hermitian Hamiltonians
• Altermagnetism: spin-momentum locked phase protected by non-relativistic symmetries
• Anomalous edge state in a non-Hermitian lattice
• Correspondence between winding numbers and skin modes in non-hermitian systems
• Non-Hermitian Chern bands
• Crystal Hall effect in Collinear Antiferromagnets
• Observation of bulk boundary correspondence breakdown in topolectrical circuits
• Observation of non-Hermitian bulk-boundary correspondence in quantum dynamics
• Non-Hermitian robust edge states in one-dimension: Anomalous localization and eigenspace condensation at exceptional points
• Non-Hermitian skin effect and chiral damping in open quantum systems
• Giant momentum-dependent spin splitting in centrosymmetric low Z antiferromagnets
• Non-Hermitian Topology and Exceptional-Point Geometries
• Momentum-Dependent Spin Splitting by Collinear Antiferromagnetic Ordering
• Hybrid higher-order skin-topological modes in non-reciprocal systems
• Second-Order Topological Phases in Non-Hermitian Systems
• Topological Transition in a Non-Hermitian Quantum Walk
• Non-Hermitian Topological Invariants in Real Space
• Critical non-Hermitian Skin Effect
• Topological phase transition in non-Hermitian quasicrystals
• Broken Kramers' degeneracy in altermagnetic MnTe
• Giant and tunneling magnetoresistance effects from anisotropic and valley-dependent spin-momentum interactions in antiferromagnets
• Universal non-Hermitian skin effect in two and higher dimensions
• Altermagnetism: Exploring New Frontiers in Magnetism and Spintronics
• Direct observation of altermagnetic band splitting in CrSb thin films
• Observation of Non-Hermitian Skin Effect and Topology in Ultracold Atoms
• Non-Hermitian topological phenomena: A review
• Observation of hybrid higher-order skin-topological effect in non-Hermitian topolectrical circuits
• Higher-order non-Hermitian skin effect
• Topological Non-Hermitian skin effect
• Topology-Induced Spontaneous Non-reciprocal Pumping in Cold-Atom Systems with Loss
• Higher-order topological corner states induced by gain and loss
• Absence of topological insulator phases in non-Hermitian PT-symmetric Hamiltonians
• Simultaneous Observation of Topological Edge State and Exceptional Point in an Open and Non-Hermitian System
• Discovery of a metallic room-temperature d-wave altermagnet KV2Se2O
• dc Josephson Effect in Altermagnets
• Antiferroelectric Altermagnets: Antiferroelectricity Alters Magnets
• Enumeration and representation theory of spin space groups
• Landau Theory of Altermagnetism
• Non-Reciprocal gain in non-Hermitian time-Floquet Systems
• Three-dimensional mapping of the altermagnetic spin splitting in CrSb
• Altermagnetic Routes to Majorana Modes in Zero Net Magnetization
• Crystal-symmetry-paired spin-valley locking in a layered room-temperature antiferromagnet
• Spin Space Groups: Full Classification and Applications
• Continuous Phase Transition without Gap Closing in Non-Hermitian Quantum Many-Body Systems
• Enumeration of spin-space groups: Towards a complete description of symmetries of magnetic orders
• Non-Hermitian second-order skin and topological modes
• Majorana corner modes and tunable patterns in an altermagnet heterostructure
• Hybrid skin-topological modes without asymmetric couplings
• Inner Skin Effects on Non-Hermitian Topological Fractals
• Two-dimensional non-Hermitian skin effect in an ultracold Fermi gas
• Anisotropy of the anomalous Hall effect in the altermagnet candidate Mn${}_5$Si${}_3$ films
• Majorana corner and hinge modes in second-order topological insulator-superconductor heterostructures
• Altermagnetic anomalous Hall effect emerging from electronic correlations
• Creation and Manipulation of Higher-Order Topological States by Altermagnets
• Minimal Models and Transport Properties of Unconventional $p$-Wave Magnets
• Two-Dimensional Ferroelectric Altermagnets: From Model to Material Realization
• Floquet engineering of point-gapped topological superconductors
• Non-Hermitian Mott Skin Effect
• Coulomb Drag in Altermagnets
• Nonreciprocal Charge and Spin Transport Induced by Non-Hermitian Skin Effect in Mesoscopic Heterojunctions
• Topological energy braiding of the non-Bloch bands
• Observation of the anomalous Nernst effect in altermagnetic candidate Mn5Si3
• Hybrid higher-order skin-topological effect in hyperbolic lattices
• Generalized bulk-boundary correspondence in periodically driven non-Hermitian systems
• A Non-Hermitian Moiré Valley Filter
• Erratic non-Hermitian skin localization
• A brief review of hybrid skin-topological effect
• Non-Hermitian Second-Order Topological Phases and Bipolar Skin Effect in Photonic Kagome Crystals
• Altermagnetic Proximity Effect
• Localized states and skin effect around non-Hermitian impurities in tight-binding models
• Non-Hermitian second-order topological superconductors
• Emergence of tunable exceptional points in altermagnet-ferromagnet junctions
• Observation of disorder-induced boundary localization
• Pseudomagnetic suppression of non-Hermitian skin effect
• Floating Edge Bands in the Bernevig-Hughes-Zhang model with Altermagnetism
• Fingerprint of Non-Hermiticity in d-wave Altermagnet
• STM observation of the hinge-states of bismuth nanocrystals
• Theory for the spectral splitting exponent of exceptional points
• Altermagnetism and its induced higher-order topology on the Lieb lattice