Half-Quantized Hall Metal and Marginal Metal in Disordered Magnetic Topological Insulators

Abstract

A semimagnetic topological insulator -- a heterostructure combining a topological insulator with a ferromagnet -- exhibits a half-quantized Hall effect, characterized by a quantized Hall conductance of $\frac{1}{2}\frac{e^2}{h}$ (where $e$ is the elementary charge and $h$ is the Planck constant), which reinforces the established understanding of topological phenomena in condensed matter physics. However, its stability in realistic, disordered systems remains poorly understood. Here, we demonstrate the robustness of the half-quantized Hall effect in weakly disordered systems, stemming from a single gapless Dirac cone of fermions and coexisting with weak antilocalization due to the $\pi$ Berry phase that suppresses backscattering. Furthermore, we uncover a marginal metallic phase emerging between weak antilocalization and Anderson insulation -- a transition that defies conventional metal-insulator transitions by lacking an isolated critical point -- where both conductance and normalized localization length exhibit scale invariance, independent of system size. The half-quantized Hall metal and the marginal metallic phase challenge existing localization theories and provide insights into disorder-driven topological phase transitions in magnetic topological insulators, opening avenues for exploring quantum materials and next-generation electronic devices.

29 pages, 6 figures

References in corpus (22)

• Quantized Anomalous Hall Effect in Magnetic Topological Insulators
• Anderson Transitions
• The Kernel Polynomial Method
• Signatures of Fractional Quantum Anomalous Hall States in Twisted MoTe2 Bilayer
• Observation of Fractionally Quantized Anomalous Hall Effect
• Trajectory of Anomalous Hall Effect toward the Quantized State in a Ferromagnetic Topological Insulator
• Colloquium: Quantum anomalous Hall effect
• Topological delocalization of two-dimensional massless Dirac fermions
• Topological Anderson Insulator in Three Dimensions
• Localization and Kosterlitz-Thouless Transition in Disordered Graphene
• Quantum criticality and minimal conductivity in graphene with long-range disorder
• Half-Quantized Hall Effect and Power Law Decay of Edge Current Distribution
• Half-Quantized Hall Effect at the Parity-Invariant Fermi Surface
• Disorder-Induced Quantum Phase Transitions in Three-Dimensional Second-Order Topological Insulators
• Half-Quantized Helical Hinge Currents in Axion Insulators
• Anisotropic Topological Anderson Transitions in Chiral Symmetry Classes
• Signature of Parity Anomaly: Crossover from One Half to Integer Quantized Hall Conductance in a Finite Magnetic Field
• Weak quantization of non-interacting topological Anderson insulator
• Metal-insulator transition in a 2D system of chiral unitary class
• Quarter-quantized thermal Hall effect with parity anomaly
• Topological effect on the Anderson transition in chiral symmetry classes
• Anderson Critical Metal Phase in Trivial States Protected by Average Magnetic Crystalline Symmetry

Cited by in corpus (1)

• Parity Anomalous Semimetal with Minimal Conductivity Induced by an In-Plane Magnetic Field