Spin transport properties of a Dresselhaus-polygonal quantum ring

Abstract

We propose a theoretical method to investigate the effect of the Dresselhaus spin–orbit coupling (DSOC) on the spin transport properties of a regular polygonal quantum ring with an arbitrary number of segments. We find that the DSOC can break the time reversal symmetry of the spin conductance in a polygonal ring and that this property can be used to reverse the spin direction of electrons in the polygon with the result that a pure spin up or pure spin down conductance can be obtained by exchanging the source and the drain. When the DSOC is considered in a polygonal ring with Rashba spin–orbit coupling (RSOC) with symmetric attachment of the leads, the total conductance is independent of the number of segments when both of the two types of spin–orbit coupling (SOC) have the same value. However, the interaction of the two types of SOC results in an anisotropic and shape-dependent conductance in a polygonal ring with asymmetric attachment of the leads. The method we proposed to solve for the spin conductance of a polygon can be generalized to the circular model.

Spin transport in a chain of polygonal quantum rings with Dresselhaus spin–orbit coupling

“…is independent of the number of the segments in the ring. [13] Therefore, unlike the spin conductance through a single polygonal ring with DSOC, the spin conductance for a chain with DSOC depends on the number of segments that make up the polygons.…”

“…This work resulted in a new theoretical platform for electron spin transport in a quantum network. Inspired by these promising predictions, several theoretical and experimental studies have reported on the spin transport properties of polygonal structures [9][10][11][12][13][14][15][16] and the quantum transport properties of one-dimensional quantum chains. [17][18][19][20][21] The experimental realization of transport through an array of square loops with RSOC has been discussed by Koga et al [9] Bercioux et al [17] studied the quantum transport through a chain with diamond shaped subunits (squares joined at the corners) in the presence of RSOC and a magnetic field.…”

Current-induced nonequilibrium spin polarization in semiconductor-nanowire/s-wave superconductor junctions with strong spin–orbit coupling

“…The spin-orbit coupling may arise either from structural or inversion asymmetry of the semiconductor, which are termed Rashba or Dresselhaus spinorbit coupling in the literature. [36][37][38][39] We denote the strength of Rashba spin-orbit coupling as α R and the strength of Dresselhaus spin-orbit coupling as β D . The energy gap in the superconductor (S) region is denoted as ∆ .…”