Temperature Enhancement of Thermal Hall Conductance Quantization

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Topological Phases

Background:

• The search for non-Abelian quasiparticles is a significant area of research, yet direct experimental probes remain scarce.
• A key signature of non-Abelian phases is a quantized thermal Hall conductance, observed recently in quantum-Hall systems and magnetic insulators.

Purpose of the Study:

• To investigate whether nontopological phases can exhibit signatures resembling non-Abelian quasiparticles.
• To analyze the role of quenched disorder in creating such misleading thermal Hall responses.

Main Methods:

• Theoretical analysis of thermal Hall conductance in disordered systems.
• Numerical simulations to provide evidence for the proposed mechanism.

Main Results:

• Nontopological "thermal metal" phases, arising from quenched disorder, can closely approximate the quantized thermal Hall response characteristic of non-Abelian phases.
• The observed quantization in these disordered systems paradoxically improves with increasing temperature, unlike in gapped systems.

Conclusions:

• Disordered "thermal metal" phases present a potential experimental challenge, possibly being misinterpreted as non-Abelian quasiparticles.
• The temperature dependence of the thermal Hall response in disordered systems offers a distinguishing characteristic from true non-Abelian phases.