Interplay of the Rashba and Dresselhaus spin‐orbit coupling in the optical spin susceptibility of 2D electron systems

Abstract

Published online zzz PACS 73.63. Kv, 73.21.La, 72.25.Dc We present calculations of the frequency-dependent spin susceptibility tensor of a two-dimensional electron gas with competing Rashba and Dresselhaus spin-orbit interaction. It is shown that the interplay between both types of spin-orbit coupling gives rise to an anisotropic spectral behavior of the spin density response function which is significantly different from that of vanishing Rashba or Dresselhaus case. Strong resonances are developed in the spin susceptibility as a consequence of the angular anisotropy of the energy spin-splitting. This characteristic optical modulable response may be useful to experimentally probe spin accumulation and spin density currents in such systems.Copyright line will be provided by the publisher Electrical manipulation of the electron and hole spins without the need of ferromagnetic materials and/or external magnetic fields is nowadays one of the central aspects in the field of spintronics. [1, 2, 3] The presence of a sizeable spin-orbit interaction (SOI) in low-dimensional semiconductor structures and its modulation possibility (through electrical gating) make it a very prominent mechanism for the access and manipulation of the carriers spin states.It has been established that the dominant contributions to the SOI in quasi-two dimensional electron gases (2DEG) are the so called Rashba and Dresselhaus SO couplings.[4] The former results from the asymmetry of the confining potential that creates the 2DEG, while the latter arises due to the inversion asymmetry of the bulk. Several interesting effects and spin-based devices relying in these SOI mechanisms have been predicted and proposed in the last few years. For instance, the celebrated spin transistor proposed by Datta and Das [5], and its recent non-ballistic version [6]. An intrinsic spin Hall effect in which a transverse spin current is driven by a dc electric field (without a net charge current) has been also predicted to occur due to SOI effects. [7,8,9] More recently, a spin (Hall) accumulation has been observed through optical measurements [10,11,12], and lately, a purely electrical detection of a spin Hall current has been reported.[13] Electric-field-induced spin orientation in SOI coupled systems [14,15,16,17,18] and strained semiconductors has been also explored. [19] On the other hand, the spin-splitting caused by SOI in electron systems opens the possibility of resonant effects via transitions between the spin-split states as a response to alternating electric fields. [20,21,22,23,24,25] The importance of the study of such SOI effects in the dynamical regime (frequency dependent response) has been emphasized by several authors studying a variety of physical aspects, including spin and charge optical conductivities [22], optical absorption spectra [25,26], optical control of the spin Hall current through intense ac probing fields [27], electron-electron interaction effects [28,29], electronphonon interaction on spin Hall currents [30], plasmon modes [23,31...

Spin-torque contribution to the ac spin Hall conductivity

“…43 obtained there via the spin-susceptiblity calculation. 44 Note also that the second term of Eq. ͑16͒ vanishes for = 0, while the first one, when added to Eq.…”

Superconductivity in a two-dimensional superconductor with Rashba and Dresselhaus spin–orbit couplings

“…1(c). It is shown that spin-splitting vanishes along a certain direction in this case [24], and nontrivial physical properties can be expected.…”

Rashba coupling induced spin susceptibility and magnetic phase transition of conduction electrons in monolayer graphene

“…Susceptibility using the free electron model to the electric field induced by the spin density is described 8,10 . Meanwhile the Rashba coupling plays a major role in spin susceptibility of the free electron system.…”

“…As long as the Rashba interaction is stronger than the intrinsic spin-orbit interaction, energy bands near the Dirac points of the Brillouin zone will show trigonal warping 7 . Susceptibility using the free electron model to the electric field induced by the spin density is described 8,10 . Meanwhile the Rashba coupling plays a major role in spin susceptibility of the free electron system.…”