Speaker
Description
A fundamental instability in the nonequilibrium conduction band under an
electric field bias occurs via the spontaneous emission of coherent
phonons. Analytic theory, supported by numerical calculations,
establishes that the quantum avalanche, an abrupt nonequilibrium
occupation of excited bands, results from the competition between the
collapse of the band minimum via the phonon emission and the dephasing
of the electron with the environment. The continuous avalanche
transition is a quantum phase transition with the nonequilibrium phase
diagram determined by the avalanche parameter $\beta$. We further
confirm the nature of the quantum avalanche with the temperature
dependence.
[1] X. Chen and J. E. Han, Avalanche Instability as Nonequilibrium
Quantum Criticality, Phys. Rev. B 109, 054307 (2024).
[2] J. E. Han et al, Correlated insulator collapse due to quantum
avalanche via in-gap ladder states, Nat. Comm. 14, 2936 (2023).
[3] J. Nathawat et al, Signatures of hot carriers and hot phonons in the
re-entrant metallic and semiconducting states of Moiré-gapped graphen,
Nat. Comm. 14, 1507 (2023).
