# Observation of anomalous non-Ohmic transport in current-driven nanostructures

## TL;DR

This paper reports the discovery of anomalous non-Ohmic resistance behavior in current-driven metallic nanostructures at cryogenic temperatures, linked to non-equilibrium phonon distributions, with implications for nanoscale thermal management.

## Contribution

It provides experimental evidence of current-dependent resistance not explained by Joule heating, suggesting a new phonon-related mechanism in nanostructures.

## Key findings

- Resistance depends linearly on current at low temperatures.
- Behavior transitions to Joule heating with increasing temperature.
- Non-equilibrium phonons influence electron transport at nanoscale.

## Abstract

Sufficiently large electric current applied to metallic nanostructures can bring them far out-of-equilibrium, resulting in non-Ohmic behaviors characterized by current-dependent resistance. We experimentally demonstrate a linear dependence of resistance on current in microscopic thin-film metallic wires at cryogenic temperatures, and show that our results are inconsistent with common non-Ohmic mechanisms such as Joule heating. As the temperature is increased, the linear dependence becomes smoothed out, resulting in the crossover to behaviors consistent with Joule heating. A plausible explanation for the observed behaviors is the strongly non-equilibrium distribution of phonons generated by the current. Analysis based on this interpretation suggests that the observed anomalous current-dependent resistance can provide information about phonon transport and electron-phonon interaction at nanoscale. The ability to control the properties of phonons generated by current can lead to new routes for the optimization of thermal properties of electronic nanodevices.