Paul Wenk

Control of spin helix symmetry in semiconductor quantum wells by crystal orientation

We investigate the possibility of spin-preserving symmetries due to the interplay of Rashba and Dresselhaus spin-orbit coupling in n-doped zinc-blende semiconductor quantum wells of general crystal orientation. It is shown that a conserved spin operator can be realized if and only if at least two growth direction Miller indices agree in modulus. The according spin-orbit field has in general both in-plane and out-of-plane components and is always perpendicular to the shift vector of the corresponding persistent spin helix. We also analyze higher-order effects arising from the Dresselhaus term, and the impact of our results on weak (anti)localization corrections.

Dimensional dependence of weak localization corrections and spin relaxation in quantum wires with Rashba spin-orbit coupling

The quantum correction to the conductivity in disordered quantum wires with linear Rashba spin-orbit coupling is obtained. For quantum wires with spin-conserving boundary conditions, we find a crossover from weak antilocalization to weak localization as the wire width

Trigonal warping in bilayer graphene: Energy versus entanglement spectrum

W

Weak (anti)localization in tubular semiconductor nanowires with spin-orbit coupling

is reduced using exact diagonalization of the Cooperon equation. This crossover is due to the dimensional dependence of the spin relaxation rate of conduction electrons, which becomes diminished, when the wire width

Spontaneous magnetization in the presence of nanoscale inhomogeneities in diluted magnetic systems

W

Direction dependence of spin relaxation in confined two-dimensional systems

is smaller than the bulk spin precession length

Magnetoconductance correction in zinc-blende semiconductor nanowires with spin-orbit coupling

{L}_{\text{SO}}

Conserved spin quantity in strained hole systems with Rashba and Dresselhaus spin-orbit coupling

. We thus confirm previous results for small wire width,

Signatures of spin-preserving symmetries in two-dimensional hole gases

W/{L}_{\text{SO}}\ensuremath{\lesssim}1

Plasmons in spin-orbit coupled two-dimensional hole gas systems

[S. Kettemann, Phys. Rev. Lett. 98, 176808 (2007)], where only the transverse 0 modes of the Cooperon equation had been taken into account. We find that spin helix solutions become stable for arbitrary ratios of linear Rashba and Dresselhaus coupling in narrow wires. For wider wires, the spin relaxation rate is found to be not monotonous as function of wire width