Universal dielectric loss in amorphous solids from simultaneous bias and microwave field

TL;DR

This paper derives a universal formula for dielectric loss in amorphous solids caused by two-level systems under combined bias and microwave fields, revealing a maximum loss tangent and a method to extract material parameters.

Contribution

It introduces a theoretical framework for understanding nonequilibrium dielectric loss in glasses under simultaneous bias and microwave fields, connecting it to Landau-Zener theory.

Findings

Loss tangent approaches a universal maximum at high fields and sweep rates.

Derived a loss function to extract TLS parameters from experimental data.

Predicted the behavior of dielectric loss using Landau-Zener theory.

Abstract

We derive the ac dielectric loss in glasses due to resonant processes created by two-level systems and a swept electric field bias. It is shown that at sufficiently large ac fields and bias sweep rates the nonequilibrium loss tangent created by the two fields approaches a universal maximum determined by the bare linear dielectric permittivity. In addition this nonequilibrium loss tangent is derived for a range of bias sweep rates and ac amplitudes and show that the loss tangent creates a predicted loss function that can be understood in a Landau-Zener theory and which can be used to extract the TLS density, dipole moment, and relaxation rate.