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Project

Photo-transient metallization dynamics in the strongly correlated oxide V2O3: a temporally and spatially resolved perspective

The reversible and ultrafast manipulation of the electronic properties of materials is one of the main goals of the research in solid state physics and materials science. This achievement would pave the way to the development of solid-state devices which could be reversibly switched at THz frequencies. Currently, resistive switching can be obtained on many materials, such as metal oxides and chalcogenides, by applying an electric field which mainly induces Joule heating and the formation of local conductive paths in which the oxygen content is altered. In both cases, the deformation of the lattice structure constitutes a bottleneck in the switching speed and stabilizes the new phase preventing a fast recovery of the original resistive state. Among the many materials investigated for the purpose, Mott insulators are probably the most promising. In these materials, a metal-to-insulator transition, characterized by a resistivity change of several orders of magnitude, can be induced by electric or optical means. In particular, the strongly correlated vanadium oxides are considered as prototypical systems for exploring the fundamental mechanisms of the resistive transition. Here we propose a new route towards the reversible and ultrafast control of the resistivity of vanadium oxides, which is based on the combination of electrical and optical stimuli. While an under-threshold bias is applied to the system, the non-thermal population of the electronic bands created by sub-picosecond laser pulses can be exploited as a seed to induce the transition. The combined role of the bias and optical excitations could result in a homogeneous switching behaviour on a timescale faster than the effective local heating of the system, thus driving the metal-to-insulator transition along a non-thermal pathway inaccessible through conventional techniques.

Date:7 Sep 2016 →  10 Dec 2020
Keywords:vanadium oxides, strongly correlated oxides, ultrafast optical spectroscopy
Disciplines:Condensed matter physics and nanophysics
Project type:PhD project