Ultrafast THz Field Control of Electronic and Structural Interactions in Vanadium Dioxide

TL;DR

This study demonstrates ultrafast control of electronic and structural interactions in vanadium dioxide using intense electric fields, revealing distinct timescales for electronic gap collapse and lattice change.

Contribution

It introduces a method to disentangle and control electronic and structural dynamics in correlated materials with ultrafast electric fields.

Findings

Partial collapse of the insulating gap within 1 ps

Electronic reconfiguration triggers lattice symmetry change

Kinetic energy increase drives the process

Abstract

Vanadium dioxide, an archetypal correlated-electron material, undergoes an insulator-metal transition near room temperature that exhibits electron-correlation-driven and structurally-driven physics. Using ultrafast optical spectroscopy and x-ray scattering we show that these processes can be disentangled in the time domain. Specifically, following intense sub-picosecond electric-field excitation, a partial collapse of the insulating gap occurs within the first ps. Subsequently, this electronic reconfiguration initiates a change in lattice symmetry taking place on a slower timescale. We identify the kinetic energy increase of electrons tunneling in the strong electric field as the driving force, illustrating a novel method to control electronic interactions in correlated materials on an ultrafast timescale.