Phys.org July 24, 2023
The significant discrepancy observed between the predicted and experimental switching fields in correlated insulators under a DC electric field far-from-equilibrium necessitates a reevaluation of current microscopic understanding.
An international team of researchers (USA – SUNY Buffalo, France, South Korea) has shown that an electron avalanche can occur in the bulk limit of such insulators at arbitrarily small electric field by introducing a generic model of electrons coupled to an inelastic medium of phonons. The quantum avalanche arose because of the generation of a ladder of in-gap states, created by a multi-phonon emission process. Hot-phonons in the avalanche triggered a premature and partial collapse of the correlated gap. The phonon spectrum dictated the existence of two-stage versus single-stage switching events which they associated with charge-density-wave and Mott resistive phase transitions, respectively. According to the researchers the behavior of electron and phonon temperatures, as well as the temperature dependence of the threshold fields, demonstrated how a crossover between the thermal and quantum switching scenarios emerges within a unified framework of the quantum avalanche… read more. Open Access TECHNICAL ARTICLEÂ
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Avalanche mechanism. Credit: Nature Communications volume 14, Article number: 2936 (2023)