Detecting the Néel vector of altermagnet by attaching a topological insulator and crystalline valley-edge insulator

Abstract

In order to detect the Néel vector of an altermagnet, we investigate topological phases in a bilayer system composed of an altermagnet and a two-dimensional topological insulator described by the Bernevig-Hughes-Zhang model. A topological phase transition occurs from a first-order topological insulator to a trivial insulator at a certain critical altermagnetization if the Néel vector of altermagnet is along the $x$ axis or the $y$ axis. It is intriguing that valley-protected edge states emerge along the Néel vector in this trivial insulator, which are as stable as the topological edge states. We name it a crystalline valley-edge insulator. On the other hand, the system turns out to be a second-order topological insulator when the Néel vector is along the $z$ axis. The tunneling conductance has a strong dependence on the Néel vector. In addition, the band gap depends on the Néel vector, which is measurable by optical absorption. Hence, it is possible experimentally to detect the Néel vector by measuring tunneling conductance and optical absorption.

6 pages, 6 figures

References in corpus (21)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Observation of spin splitting torque in a collinear antiferromagnet RuO2
• Broken Kramers' degeneracy in altermagnetic MnTe
• Tilted spin current generated by the collinear antiferromagnet RuO2
• Observation of spin-splitter torque in collinear antiferromagnetic RuO${}_2$
• Coupling the valley degree of freedom to antiferromagnetic order
• Antiferromagnetism in RuO${}_2$ as $d$-wave Pomeranchuk instability
• Quantum conductance of graphene nanoribbons with edge defects
• Observation of Giant Band Splitting in Altermagnetic MnTe
• Topological Superconductivity in Two-Dimensional Altermagnetic Metals
• Coherent transport in graphene nanoconstrictions
• Spin-Valley Optical Selection Rule and Strong Circular Dichroism in Silicene
• Topological transition from nodal to nodeless Zeeman splitting in altermagnets
• Perovskite as a spin current generator
• Majorana corner modes and tunable patterns in an altermagnet heterostructure
• Saturation of the anomalous Hall effect at high magnetic fields in altermagnetic RuO2
• Spatial distribution of local currents of massless Dirac fermions in quantum transport through graphene nanoribbons
• Creation and Manipulation of Higher-Order Topological States by Altermagnets
• Interplay between altermagnetism and nonsymmorphic symmetries generating large anomalous Hall conductivity by semi-Dirac points induced anticrossings
• I-V curve signatures of nonequilibrium-driven band gap collapse in magnetically ordered zigzag graphene nanoribbon two-terminal devices

Cited by in corpus (20)

• Third-order and fifth-order nonlinear spin-current generation in $g$-wave and $i$-wave altermagnets, and perfectly nonreciprocal spin-current in $f$-wave magnets
• Staggered Dzyaloshinskii-Moriya inducing weak ferromagnetism in centrosymmetric altermagnets and weak ferrimagnetism in noncentrosymmetric altermagnets
• Topological insulators and superconductors based on $p$-wave magnets,electrical control and detection of a domain wall
• Intrinsic nonlinear conductivity induced by quantum geometry in altermagnets and measurement of the in-plane Néel vector
• Interplay of Altermagnetic Order and Wilson Mass in the Dirac Equation: Helical Edge States without Time-Reversal Symmetry
• Bulk photovoltaic effects in altermagnets
• Out-of-plane Edelstein effects: Electric-field induced magnetization in $p$-wave magnets
• Field-sensitive dislocation bound states in two-dimensional $d$-wave altermagnets
• Altermagnetism Induced Topological Phase Transitions in Kane-Mele Model
• Purely electrical detection of the spin-splitting vector in $p$-wave magnets based on linear and nonlinear conductivities
• Floating Edge Bands in the Bernevig-Hughes-Zhang model with Altermagnetism
• Quantum geometry and elliptic optical dichroism in $p$-wave magnets
• Light-induced Floquet spin-triplet Cooper pairs in unconventional magnets
• Quantum geometry and $X$-wave magnets with $X=p,d,f,g,i$
• Almost half-quantized planar Hall effects in $X$-wave magnets with $X=p,d,f,g,i$
• Altermagnetism and its induced higher-order topology on the Lieb lattice
• Tunneling magnetoresistance in a junction made of $X$-wave magnets with $X=p,d,f,g,i$
• Quantum anomalous Hall effect with tunable Chern numbers induced by d-wave sublattice-staggered altermagnetism
• Interface controlled Berry phase and anisotropic spin-charge conversion in altermagnet-topological insulator bilayers
• Current switching behavior mediated via hinge modes in higher-order topological phases using altermagnets