Spin-dependent coherent transport in a double quantum dot system

TL;DR

This paper investigates how spin-dependent effects influence resonant tunneling in a double quantum dot system, revealing the impact of magnetic fields, spin-orbit coupling, and magnetic flux on conductance spin structures.

Contribution

It demonstrates the conditions under which spin-resolved conductance features appear and how they are affected by spin-orbit coupling and magnetic flux in a double quantum dot system.

Findings

Spin-resolved conductance peaks appear in the coherent regime with small Zeeman splitting.

Spin-orbit coupling degrades the spin-resolved structure due to Fermi surface deformation.

Aharonov-Bohm flux destroys the conductance spin structure.

Abstract

We study spin-resolved resonant tunneling in a system of two quantum dots sandwiched between doped quantum wells. In the coherent (Dicke) regime, i.e., when quantum dot separation is smaller than the Fermi wavelength in a two-dimensional electron gas in quantum wells, application of an in-plane magnetic field leads to a pronounced spin-resolved structure of the conductance peak lineshape even for very small Zeeman splitting of the quantum dots' resonant levels. In the presence of electron-gas spin-orbit coupling, this spin-resolved structure gets washed out due to Fermi surface deformation in the momentum space. We also show that Aharonov-Bohm flux penetrating the area enclosed by electron tunneling pathways completely destroys conductance spin structure.