Charge dynamics and Kondo effect in single-electron traps in field-effect transistors

Abstract

We study magneto-electric properties of single electron traps in metal-oxide-semiconductor field effect transistors. Using a microscopic description of the system based on the single-site AndersonHolstein model, we derive an effective low energy action for the system. The behavior of the system is characterized by simultaneous polaron tunneling (corresponding to the charging and discharging of the trap) and Kondo screening of the trap spin in the singly occupied state. Hence, the obtained state of the system is a hybrid between the Kondo regime, typically associated with single electron occupancy, and the mixed valence regime, associated with large charge fluctuations. In the presence of a strong magnetic field, we demonstrate that the system is equivalent to a two level-level system coupled to an Ohmic bath, with a bias controlled by the applied magnetic field. Due to the Kondo screening, the effect of the magnetic field is significantly suppressed in the singly occupied state. We claim that this suppression can be responsible for the experimentally observed anomalous magnetic field dependence of the average trap occupancy in Si − Si02 field effect transistors.

Molecular transport junctions: vibrational effects

“…in the context of dynamical image effects in scanning tunnelling spectroscopy [262][263][264] where marked differences of the dynamical image potential from its static analogue were found when the tunnelling time is of the order of or shorter than the inverse surface plasmon frequency. Also, tunnelling suppression resulting from strong correlations associated with electron-electron and electron-phonon interactions in single electron traps in metal-oxidesemiconductor field effect transistors was studied using this approach [265,266]. Path integrals on the Keldysh contour were used to study effects of strong electron-phonon interactions in tunnelling of electrons via magnetic impurities [267], inelastic tunnelling in quantum point contacts [268] and in resonance tunnelling [269] and non-linear conduction phenomena associated with electron-phonon interactions [92,270,271].…”

Nonequilibrium diagrammatic technique for Hubbard Green functions

“…[85] using the Schrieffer-Wolf transformation of the Hubbard Hamiltonian and evaluating Golden rule rates after the transformation. Noting that result of the Schrieffer-Wolf transformation can be effectively achieved within second order perturbation theory [86], and keeping in mind that in the Hubbard NEGF expression for current,…”