Spin-dependent coherent transport in a double quantum dot system

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 two-dimensional electron gas in quantum wells, application of an inplane magnetic field leads to a pronounced spin-resolved structure of conductance peak lineshape even for very small Zeeman splitting of quantum dots' resonant levels. In the presence of electron gas spin-orbit coupling, this spin-resolved structure is washed out due to Fermi surface deformation in the momentum space. We also show that Aharonov-Bohm flux penetrating the area enclosed by tunneling electron pathways completely destroys the conductance spin structure.

Enhanced spin-dependent thermopower in a double-quantum-dot sandwiched between two-dimensional electron gases*

“…The 4 × 4 matrix Σ = ΣL + ΣR is the self-energy due to coupling between the dots and 2DEGs. Its matrix elements in spin and configuration space are given by [45]…”

“…Experimentally, QDs are mainly defined either self-assembly or electrically in two-dimensional gases (2DEGs). [44][45][46] Here we investigate the SSE in a system composing of double QDs (DQD) embedded between the left and right 2DEGs which are prepared in doped quantum wells [44,45] held at different temperatures as shown in Fig. 1.…”

Strong coupling regime in coherent electron transport in periodic quantum nanostructures

“…Due to QDC periodicity, tunneling between QDC and QWs gives rise to a quasimomentum p along the y direction that conserves across the QW/QDC/QW system [36,41]. The 1DEG momentum space splits into Bloch bands, k → g n + p, where g n = k a n is the nth Bloch band wave vector (k a = 2π/a is the reciprocal lattice vector, and n is an integer).…”