Universal subgap optical conductivity in quasi-one-dimensional Peierls systems

TL;DR

This paper presents a universal scaling law for subgap optical conductivity in quasi-one-dimensional Peierls systems, validated by experiments on materials like KCP(Br) and trans-polyacetylene, using a novel exact Green function method.

Contribution

Introduces a new exact method to compute disorder-averaged Green functions for Peierls systems, revealing a universal subgap conductivity scaling law.

Findings

Universal subgap tail of conductivity follows a specific scaling form

Calculated spectra match experimental data on KCP(Br) and trans-polyacetylene

Method provides a precise tool for analyzing disordered quasi-1D systems

Abstract

Quasi-one-dimensional Peierls systems with quantum and thermal lattice fluctuations can be modeled by a Dirac-type equation with a Gaussian-correlated off-diagonal disorder. A powerful new method gives the exact disorder-averaged Green function used to compute the optical conductivity. The strong subgap tail of the conductivity has a universal scaling form. The frequency and temperature dependence of the calculated spectrum agrees with experiments on KCP(Br) and trans-polyacetylene.