Hyperfine-driven persistent currents in mesoscopic rings based on a 2D electron gas with Rashba spin-orbit interaction

Abstract

We present a detailed theory of induced persistent current (PC) produced by hyperfine interaction in mesoscopic rings based on a 2D-electron (hole) gas in the absence of external magnetic field. PC emerges due to combined action of the hyperfine interaction of charge carriers with polarized nuclei, spin-orbit interaction and Berry phase.

Electronic transport through a nuclear-spin-polarization-induced quantum wire

“…In the first case ͑the strong relaxation limit͒ t l ϳT 1 /2 ln͓m*d 2 ( B B 0 ) 2 /ប 2 k B T*͔. In the second case ͑the diffusion regime͒ t l ϳt 0 ( B B 0 /k B T*) 2 . Let us estimate the half-width of the wire ␣ Ϫ1 at tϳt l .…”

“…6,4 The spin splitting ( B B h f ) due to such hyperfine magnetic field is comparable to the Fermi energy of 2DEG. Thus, if the gate potential U gate is more than 1,2 , then all the electrons in the region, where nuclear-spins are polarized, will occupy the energetically more favorable states with the spins opposite to B h f . And, furthermore, the nuclear polarization acts on the electrons as the effective confining potential V con f ϭϪ B B h f .…”

“…It was shown there and later discussed in Ref. 2 that the inhomogeneous external hyperfine magnetic field, acting on the charge carriers confined to move in a ring, influence the quantum interference ͑mesoscopic͒ phenomena and can induce the persistent current with some interesting physical features. In Ref.…”

“…There has been much recent theoretical [1][2][3] and experimental 4 -7 interest in the peculiarities of the electron transport in mesoscopic systems with highly polarized nuclear spins. In Ref.…”

“…[9][10][11] The dependence of the conductance at ''zero'' temperature on the number of transverse modes in the conductor is given by the Landauer formula: 12 Gϭ 2e 2 …”