Correlation-driven metal-insulator transition in Cu$_x$V$_2$O$_5$ nanobeams probed by resistance noise spectroscopy

Nanoscale vanadium oxide bronzes have attracted interest due to the interesting phenomena they exhibit ranging from charge ordering, superconductivity and metal insulator transitions. We present results from a transport and resistance noise study of single crystalline nanobeams of ${\beta'-\textrm{Cu}_x\textrm{V}_2\textrm{O}_5}$. Resistance noise spectroscopy is a sensitive tool to understand local electronic and structural changes across a phase transition and we employ the method to understand the metal-insulator transition in individual nanobeams of ${\beta'-\textrm{Cu}_x\textrm{V}_2\textrm{O}_5}$. The nanobeams show a metal-insulator transition upon cooling from room temperature with a T$_{MI}\sim$ 210 K. The low-frequency (< 1 Hz) noise magnitude shows a bump-like increase near the phase transition and deviation from a simple 1/f behavior. The probability density function of the resistance fluctuations shows signatures of non-Gaussian fluctuators near the transition and can be interpreted as a strong indicator of a correlation-driven phase transition. The roles of Mott physics, charge ordering and further avenues to tune the transition for potential applications as Mott field effect transistors will be discussed.