# Strategy for accurate thermal biasing at the nanoscale

## TL;DR

This paper investigates the use of contact heating for precise thermal biasing in nanoscale conductors, highlighting calibration challenges and solutions for improved thermoelectric measurements.

## Contribution

It demonstrates how to calibrate thermal biasing in nanoscale devices by analyzing the impact of leads and provides a method for accurate thermometry at the nanoscale.

## Key findings

- Nanoscale metallic constrictions act as diffusive conductors with negligible electron-phonon relaxation.
- Lead geometry and material significantly affect thermal biasing accuracy.
- Calibration can be achieved by knowing the heater resistance, enabling precise thermoelectric measurements.

## Abstract

We analyze the benefits and shortcomings of a thermal control in nanoscale electronic conductors by means of the contact heating scheme. Ideally, this straightforward approach allows one to apply a known thermal bias across nanostructures directly through metallic leads, avoiding conventional substrate intermediation. We show, by using the average noise thermometry and local noise sensing technique in InAs nanowire based devices, that a nanoscale metallic constriction on a SiO2 substrate acts like a diffusive conductor with negligible electron-phonon relaxation and non-ideal leads. The non-universal impact of the leads on the achieved thermal bias -- which depends on their dimensions, shape and material composition -- is hard to minimize, but is possible to accurately calibrate in a properly designed nano-device. Our results allow to reduce the issue of the thermal bias calibration to the knowledge of the heater resistance and pave the way for accurate thermoelectric or similar measurements at the nanoscale.