Influence of the substrate-induced strain and irradiation disorder on the Peierls transition in TTF-TCNQ microdomains

TL;DR

This study investigates how substrate strain, finite size, and irradiation defects affect the Peierls transition in TTF-TCNQ microdomains, revealing complex conductivity behavior and comparing with thin film data.

Contribution

It introduces a detailed analysis of substrate-induced strain and irradiation effects on the Peierls transition in isolated TTF-TCNQ microdomains, using advanced measurement techniques.

Findings

Variable range hopping conductivity observed

Crossover in Peierls transition behavior

Comparison with irradiated thin film data

Abstract

The influence of the combined effects of substrate-induced strain, finite size and electron irradiation-induced defects have been studied on individual micron-sized domains of the organic charge transfer compound tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) by temperature-dependent conductivity and current-voltage measurements. The individual domains have been isolated by focused ion beam etching and electrically contacted by focused ion and electron beam induced deposition of metallic contacts. The temperature-dependent conductivity follows a variable range hopping behavior which shows a crossover of the exponent as the Peierls transition is approached. The low temperature behavior is analyzed within the segmented rod model of Fogler, Teber and Shklowskii, as originally developed for a charge-ordered quasi one-dimensional electron crystal. The results are compared with data obtained on as-grown and electron irradiated epitaxial TTF-TCNQ thin films of the two-domain type.