A nonlinear, geometric Hall effect without magnetic field

Nicholas B Schade; David I Schuster; Sidney R Nagel

doi:10.1073/pnas.1916406116

A nonlinear, geometric Hall effect without magnetic field

Proc Natl Acad Sci U S A. 2019 Dec 3;116(49):24475-24479. doi: 10.1073/pnas.1916406116. Epub 2019 Nov 18.

Authors

Nicholas B Schade^{1

2

3}, David I Schuster^{4

2}, Sidney R Nagel^{4

2

3}

Affiliations

¹ Department of Physics, The University of Chicago, Chicago, IL 60637; nschade@uchicago.edu.
² The James Franck Institute, The University of Chicago, Chicago, IL 60637.
³ The Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637.
⁴ Department of Physics, The University of Chicago, Chicago, IL 60637.

Abstract

The classical Hall effect, the traditional means of determining charge-carrier sign and density in a conductor, requires a magnetic field to produce transverse voltages across a current-carrying wire. We demonstrate a use of geometry to create transverse potentials along curved paths without any magnetic field. These potentials also reflect the charge-carrier sign and density. We demonstrate this effect experimentally in curved wires where the transverse potentials are consistent with the doping and change polarity as we switch the carrier sign. In straight wires, we measure transverse potential fluctuations with random polarity demonstrating that the current follows a complex, tortuous path. This geometrically induced potential offers a sensitive characterization of inhomogeneous current flow in thin films.

Keywords: Hall effect; graphene; surface charge; transverse potential.