Leonid Semenovich Muratov

Light-induced electron transfer counter to an electric-field force in an asymmetric double quantum well

Abstract Electron transfer counter to an electric-field force is predicted for an asymmetrical double quantum well subjected to a dc bias in response to optical (far IR) excitation of an intersubband electronic transition. This transfer exhibits a resonance enhancement when the bias electric field aligns the excited levels in the wide and narrow wells. The transfer effect is driven by the quantum- mechanical delocalization caused by the coherent resonant tunneling which prevails over the electric force. The effect brings about a photoinduced increase of the potential difference at the double well and a transient electric current opposite to the direction favored by the bias.

Spatial Redistribution of Niobium Additives Near Nickel Surfaces

The spatial redistribution of niobium atoms near the surface of pure nickel has been considered in the low niobium concentration limit. The calculation of free energy includes lattice relaxation around niobium atoms by using molecular dynamics (MD) incorporating atomistic potentials based on ab-initio quantum mechanical calculations and includes vibrational entropy phenomenologically within the local harmonic approximation.

Possibility of intrinsic optical (far-IR) bistability in an asymmetric double quantum well

Abstract A new type of optical bistability in a double quantum well is predicted. This is a pure intrinsic bistability which is not accompanied by any dc current in an external circuit and requires no source of electric energy. The effect is based on counterfield electron transfer and is driven and controlled by far-IR radiation resonant to an intersubband transition. Bistable switching and hysteresis can be monitored either electrically or optically. Theory shows the effect to be readily observable.

Photoinduced Electron Transfer Counter to the Bias Field in Coupled Quantum Wells

Abstract : Optical excitation of electrons in an asymmetric double quantum well is theoretically examined. The well is biased to align the excited levels and permit resonant electron tunneling. Emphasis is made on the photoinduced transfer of electrons counter to the bias electric field force. A density- matrix approach is developed to describe optical excitations in the presence of an arbitrary dephasing. The excitation profiles obtained for cases of different dephasing reveal the full range of tunneling coupling between the wells from completely coherent to incoherent (stepwise).