Electronic Heat Transport Across a Molecular Wire: Power Spectrum of Heat Fluctuations

TL;DR

This paper investigates the frequency-dependent fluctuations of electronic heat current in a molecular wire, revealing complex behavior beyond linear response and deriving the power spectral density using Green function methods.

Contribution

It introduces a novel derivation of the finite frequency power spectral density of heat fluctuations in a molecular wire, highlighting differences from electric noise and zero-temperature asymptotics.

Findings

Heat noise intensity depends on frequency even at zero temperature.

The power spectral density simplifies at zero frequency, revealing distinct behaviors in low- and high-frequency regimes.

Heat transport exhibits complex spectral features beyond linear response theory.

Abstract

With this study we analyze the fluctuations of an electronic only heat current across a molecular wire. The wire is composed of a single energy level which connects to two leads which are held at different temperatures. By use of the Green function method we derive the finite frequency power spectral density (PSD) of the emerging heat current fluctuations. This result assumes a form quite distinct from the power spectral density of the accompanying electric current noise. The complex expression simplifies considerably in the limit of zero frequency, yielding the heat noise intensity. The heat noise intensity still depends on the frequency in the zero-temperature limit, assuming different asymptotic behaviors in the low- and high-frequency regimes. These findings evidence that heat transport across molecular junctions can exhibit a rich structure beyond the common behavior which emerges in the linear response limit.