Switchable Quantized Signal between Longitudinal Conductance and Hall Conductance in Dual Quantum Spin Hall Insulator...

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• Topological insulators (TIs) in 2D materials offer unique platforms for studying quantized responses due to their in-gap metallic states.
• Monolayer TaIrTe4 recently demonstrated the quantum spin Hall effect, characterized by quantized longitudinal conductance, a rare observation in 2D TIs.
• Nontrivial Z2 topological charges in monolayer TaIrTe4 are associated with charge neutrality and van Hove singularity points, featuring correlation-effect-induced bandgaps.

Purpose of the Study:

• Investigate the switching of quantized signals between longitudinal and transversal Hall conductance in monolayer TaIrTe4.
• Explore the tunability of topological states via external magnetic fields.
• Provide a new method for verifying topological states and utilizing switchable quantum responses.

Main Methods:

• Theoretical study of monolayer TaIrTe4 using a model based on its Z2 topological phase.
• Analysis of band inversion in spin-up and spin-down channels.
• Application of perpendicular magnetic fields to induce Zeeman splitting and alter band order and Berry phase sign.

Main Results:

• The Z2 topological phase in monolayer TaIrTe4 exhibits a zero Chern number (1 - 1 = 0) due to double band inversion.
• Perpendicular magnetic fields tune the net Chern number to +2 or -2 by modifying band order and Berry phase.
• Quantized longitudinal and transversal Hall conductances can be switched by external magnetic fields.

Conclusions:

• The observed switchable quantized signals serve as an effective verification method for the topological state in monolayer TaIrTe4.
• This study presents a strategy for exploiting novel quantum topological states through switchable quantized responses.
• The findings contribute to the understanding and application of 2D topological materials in quantum technologies.