Transport Properties and Optical Conductivity of the adiabatic Su-Schrieffer-Heeger model: a showcase study for rubrene based field effect transistors

TL;DR

This study investigates the transport and optical properties of the adiabatic SSH model tailored for Rubrene FETs, revealing insights into mobility, spectral functions, and low-energy optical peaks relevant to experimental observations.

Contribution

It provides a detailed analysis of the SSH model parameters for Rubrene FETs, clarifies the spectral function's role in transport, and connects optical conductivity features with experimental data.

Findings

Mobility vanishes without energy level broadening.

Spectral function explains ARPES and transport data contradiction.

Low-energy peak in optical conductivity matches experiments.

Abstract

Transport properties, spectral function and optical conductivity of the adiabatic one-dimensional Su-Schrieffer-Heeger (SSH) model are studied with particular emphasis on the model parameters suitable for Rubrene single crystals based field effect transistors. We show that the mobility, calculated by using the Kubo formula for conductivity, vanishes unless we introduce an "ad hoc" broadening of the system energy levels. Furthermore, the apparent contradiction between angle resolved photoemission data and transport properties is clarified by studying the behavior of the spectral function. Finally, a peak in the optical conductivity at very low energy is obtained and discussed in connection with the available experimental data for Rubrene based devices.