Valley interference effects on a donor electron close to a Si/SiO2 interface

TL;DR

This paper investigates how valley interference influences the control of a donor electron near a Si/SiO2 interface, revealing oscillatory tunneling times dependent on valley-orbit coupling and distance.

Contribution

It demonstrates the impact of valley-orbit coupling on electron tunneling dynamics and how degeneracy affects interference effects near the interface.

Findings

Tunneling times oscillate with donor-interface distance due to valley interference.

Oscillations vanish when the interface ground state is degenerate.

Valley-orbit coupling modulates quantum control of donor electrons.

Abstract

We analyze the effects of valley interference on the quantum control and manipulation of an electron bound to a donor close to a Si/SiO2 interface as a function of the valley-orbit coupling at the interface. We find that, for finite valley-orbit coupling, the tunneling times involved in shuttling the electron between the donor and the interface oscillate with the interface/donor distance in much the same way as the exchange coupling oscillates with the interdonor distance. These oscillations disappear when the ground state at the interface is degenerate (corresponding to zero valley-orbit coupling).