Robustness of a persistent spin helix against a cubic Dresselhaus field in (001) and (110) oriented twodimensional electron gases
Abstract
The persistent spin helix (PSH) state in IIIV semiconductor quantum wells (QWs) is a promising candidate for spinbased applications because the PSH state realizes controllable spin orientation with long spin lifetime. Although the cubic Dresselhaus spinorbit (SO) interaction is known for breaking the PSH state in both (001)oriented and (110)oriented QWs, it is not well understood how the distinct symmetry of cubic Dresselhaus terms β_{3} between (001) and (110) QWs affects the robustness of the PSH state. Here we investigate robustness of the PSH state between (001) and (110) QWs under various strengths of cubic Dresselhaus SO interaction based on numerical Monte Carlo approach and magnetoconductance simulation, respectively, representing optical spin excitation/detection and weak localization/weak antilocalization in magnetotransport. For electron spins initialized along z ∥[001 ] in a (001) QW and x ∥[001 ] and y ∥[1 1 ̄0 ] in a (110) QW, where the spin distribution is developed with the helical spin mode, a (001) QW shows a more robust PSH state against the increase of β_{3} than does a (110) QW. This phenomenon is contrary to numerically computed magnetoconductance, where weak localization is maintained on the variation of β_{3} in a (110) QW, whereas weak antilocalization appears in a (001) QW. By deriving the spin lifetime of the PSH state in a (110) QW from a diffusion equation using a randomwalk approach, we demonstrate that such a difference arises directly from the magnitude and orientation of third angular harmonics in cubic Dresselhaus fields for (001) and (110) QWs.
 Publication:

Physical Review B
 Pub Date:
 October 2018
 DOI:
 10.1103/PhysRevB.98.165112
 Bibcode:
 2018PhRvB..98p5112I