Observation of inverse Edelstein effect in Rashba-split 2DEG between SrTiO ₃ and LaAlO ₃ at room temperature

Abstract

Gate-tunable inverse Edelstein effect is observed at room temperature in Rashba-split 2DEG at the complex oxide interface.

Theory of the Spin Galvanic Effect at Oxide Interfaces

“…Finally, when the chemical potential enters the d xz d yzbands we obtain a sizable SGE response and the overall behavior is in very good agreement with the gate voltage dependence of the spin galvanic effect as measured in Ref. [16] at T = 300 K. In contrast, the voltage dependence of the SGE response in Ref. [15] has been measured at much lower temperature T = 7 K and shows the sign change upon voltage reversal.…”

“…Quite dramatically, a sign change occurs [15] in V SGE at a particular value of µ, and has been attributed to a Lifshitz transition, where the d xz , d yz bands originating from the Ti t 2g orbitals start to be filled. Moreover, the effect strongly depends on temperature and on the number of LAO layers in the LAO/STO heterostructure [16]. In Fig.…”

“…Recently, indeed, the SGE has been observed at a silver-bismuth interface where the non-equilibrium spin polarization has been pumped by an adjacent ferromagnetic layer with a precessing magnetization [11]. Magnetic spin pumping was successively used to observe the SGE in a number of different interface systems as in ferromagnetictopological insulators [12,13] and ferromagnetic-oxide systems [14][15][16]. In the latter case, the oxide being a heterostructure of LaAlO 3 (LAO) and SrTiO 3 (STO), the complex band structure originating from the Ti orbitals may lead to a richer phenomenology [17,18], as compared to other systems where the standard continuum 2DEG model with spin-orbit split bands provides a good quantitative and qualitative understanding of the effect.…”

Room-Temperature Giant Charge-to-Spin Conversion at the SrTiO3–LaAlO3 Oxide Interface

“…Therefore, the STO/LAO heterostructure can enable potential spintronic innovations and now is attracting rising research interests. [8][9][10][11][12][13] Experimentally, Narayanapillai et al 8 have reported an extremely strong charge current induced Rashba field in the 2DEG layer, which verifies the presence of strong Rashba SOC predicted at the STO/LAO interface. Most recently, the inverse Edelstein effect at the STO/LAO interface has been demonstrated by using the spin pumping technique, [10][11][12] which shows a notable spin-to-charge conversion.…”

“…As an in-plane radio-frequency (rf) current (IRF) is applied in the STO/LAO 2DEG layer, non-equilibrium spins are generated due to the Rashba-Edelstein effect. [10][11][12]23,24 Subsequently, these spins are absorbed by the CFB layer and exert oscillating damping-like torque (DL) and/or a field-like torque (FL) on the CFB local magnetization. In addition, the rf current induces Oersted field (HRF) torque (Oe).…”