Heat Conduction and Energy Relaxation in an InAs Nanowire Approaching the Clean One-Dimensional Limit

TL;DR

This study measures heat conduction and energy relaxation in an InAs nanowire, revealing a T^2.6 electron-phonon heat flow and a characteristic length of 370 nm where phonon effects dominate.

Contribution

It provides the first quantitative analysis of energy relaxation and heat flow mechanisms in a near-ideal one-dimensional semiconductor nanowire.

Findings

Electron-phonon heat flow scales as T^2.6

Characteristic length for phonon dominance is 370 nm

Heat transport aligns with 1D electron gas models

Abstract

We investigate heat conduction and energy relaxation in an InAs semiconductor nanowire using a hybrid semiconductor-superconductor architecture. Local electronic temperatures are measured with an in-situ grown quantum dot thermometer, while controlled Joule heating is applied at different locations along the wire to probe temperature gradients at sub-kelvin temperatures. With a onedimensional heat transport model, we calculate an electron-phonon heat flow that scales as Q_{e-ph} \propto T^2.6, which is in close agreement with the T^3 dependence predicted for a clean one-dimensional electron gas coupled to a phonon bath. We further estimate a characteristic length l_{eq} = 370 nm, beyond this length scale, phonon-mediated heat transport dominates over heat conduction in our nanowire. Our results provide a quantitative measure of energy relaxation mechanisms in a onedimensional semiconductor and provide a framework for studying heat flow in low-dimensional nanostructures.