Current-induced successive structural phase transitions beyond thermal equilibrium in single-crystal VO 2

This is the authors' abstract. We don't add key points for this paper.

In solids, nonequilibrium systems driven by external energy sources, such as electric current, host unexplored physics; however, phase transitions beyond thermal equilibrium remain elusive. Here, we show that electric current induces structural phase transitions in single-crystal VO 2 . Synchrotron x-ray diffraction at room temperature reveals that a current density of 6.5 A / c m 2 disrupts V-V dimers, producing a monoclinic-to-tetragonal insulator-to-metal transition independent of Joule heating. Further increasing the current to 10 A / c m 2 triggers a discontinuous isotropic lattice expansion, stabilizing a tetragonal structure absent in thermal equilibrium. Optical microscopy and Raman spectroscopy further reveal dynamic domain motion and metastable phases. These results demonstrate direct access to hidden phases and symmetry changes beyond thermal equilibrium.