Observation of Macroscopic Nonlocal Voltage at Room Temperature

TL;DR

This paper reports the discovery of macroscopic nonlocal voltages at room temperature in certain conductors, indicating a transition from diffusive to hydrodynamic electron flow and opening new avenues for low-dissipation electronics.

Contribution

It demonstrates the existence of a nonlocal conduction state at room temperature in specific materials, challenging traditional Ohmic behavior and suggesting long-range electron momentum conservation.

Findings

Observation of nonlocal voltages (~0.1 V) across 1 mm regions.

Identification of nonlinear responses and negative local resistances.

Evidence supporting hydrodynamic electron flow as the underlying mechanism.

Abstract

Electrons in conductors suffer frequent scatterings with defects and phonons, and the diffusive macroscopic behaviors are determined by an external electric field through Ohms law. If electrons are no longer diffusive, the Ohmic description collapses. In devices composed of thin chalcogenides and YBa2Cu3O7, we observe a transition from an Ohmic conductor to a nonlocal conductor below a certain temperature. The nonlocal conductor is characterized by significant nonlocal voltages (~0.1 V) across macroscopic regions (~1 mm) that are conventionally considered to be equipotential. Nonlinear responses are an additional characteristic. Negative local resistances in a vicinal geometry support macroscopic hydrodynamic flow as the underlying mechanism, implying electron momentum conservation over incredibly long distances. This new conduction state, observable at room temperature, opens the field of nonlocal electronics and low-dissipation applications.