Length-dependent thermopower of single-molecule junctions

TL;DR

This paper theoretically investigates how the thermopower of single-molecule junctions varies with molecular length, revealing conditions for nonlinear growth and potential decrease as length increases.

Contribution

It introduces a tight-binding model to analyze length-dependent thermopower, highlighting nonlinear behaviors and length thresholds for thermopower decrease.

Findings

Thermopower can grow nonlinearly with length.

Thermopower may decrease for sufficiently long molecular bridges.

Length-dependent thermopower behavior depends on molecular parameters.

Abstract

In the present work we theoretically study the length dependence of thermopower of a single-molecule junction with a chain-like molecular bridge of an arbitrary length using a tight-binding model. We analyze conditions bringing a nonlinear growth of the thermopower accompanying the extension of the bridge length. Also, we show that the thermopower may decrease with increasing molecular length provided that the molecular bridge is sufficiently long.