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Jeudi 1 férier 2018 à 14h00 Amphi Urbain, Bâtiment N RdC
“Resistive Switch in Correlated Insulators”
The miniaturization trend in silicon-based electronic devices is limited by the size below which quantum fluctuations in the carrier density would become comparable with its average value. However, the very existence of a rigid gap between valence and conduction bands prevents scaling to lower sizes at the same time keeping a sizable density of mobile carriers.The Mott insulators can potentially overcome these limitations, leading to a huge leap in microelectronic applications.
Mott insulators are “unsuccessful metals” in which Coulomb repulsion prevents charge conduction despite a metal-like concentration of conduction electrons. The possibility to unlock the frozen carriers with an electric field offers tantalizing prospects of realizing new Mott-based microelectronic devices.
We unveil how such unlocking happens in a simple model that shows the coexistence of a stable Mott insulator and a metastable metal. We demonstrate that the electric breakdown of a Mott insulator occurs via a first-order insulator-to-metal transition characterized by an abrupt gap collapse in sharp contrast to the standard Zener breakdown.
The switch on of conduction is due to the field-driven stabilization of the metastable metallic phase. Outside the region of insulator-metal coexistence, the electric breakdown occurs through a more conventional quantum tunneling across the Hubbard bands tilted by the field. These findings help rationalizing recent experimental observations and may offer a guideline for future technological research.
