Research ArticleAPPLIED PHYSICS

Observation of inverse Edelstein effect in Rashba-split 2DEG between SrTiO3 and LaAlO3 at room temperature

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Science Advances  17 Mar 2017:
Vol. 3, no. 3, e1602312
DOI: 10.1126/sciadv.1602312
  • Fig. 1 The Rashba-split 2DEG between SrTiO3 and LaAlO3.

    (A) Schematic of 2DEG and the band alignment for the SrTiO3 and LaAlO3 heterostructures. (B) The RHEED oscillations of 4-UC LaAlO3 growing on SrTiO3. (C) The energy dispersion for a typical Rashba spin-split 2DEG. At the Fermi level, the outer and inner circles exhibit the opposite spin textures. (D) Schematic of the IEE measurements. The spin current is injected via spin pumping from Py under resonance condition. A voltage meter is used to probe the electric field generated because of the IEE of the Rashba-split 2DEG between two insulating oxides, SrTiO3 and LaAlO3.

  • Fig. 2 The electrical detection of IEE of the Rashba-split 2DEG between SrTiO3 and 6-UC LaAlO3 at 300 K.

    (A) Representative FMR spectra of the Py electrode on the SrTiO3/6-UC LaAlO3 using a vector network analyzer with an RF frequency of 6 GHz. (B) The measured voltage (black circles) as a function of the magnetic field using a signal generator with a power of 1.25 W and an RF frequency of 6 GHz. The red, blue, and green lines are fitted curves that correspond to the voltages due to IEE of the injected spin current, the Seebeck effect, and the anomalous Hall effect of Py, respectively. (C) The resonance frequency (fres) as a function of the resonance magnetic field (Hres). The solid line is a fitted curve based on the Kittel formula. (D) The half-linewidth (ΔH) versus the resonance frequency for Py on 6-UC LaAlO3 (red squares) and SiO2 (black circles) at 300 K, from which the Gilbert damping can be obtained from the slope of the linearly fitted curves.

  • Fig. 3 The temperature dependence of IEE of the Rashba-split 2DEG between SrTiO3 and 6-UC LaAlO3.

    (A) The measured voltage on SrTiO3/6-UC LaAlO3 as a function of the magnetic field at 300, 275, 250, 200, and 100 K. (B) The temperature dependence of VIEE for the Rashba-split 2DEG between SrTiO3/6-UC LaAlO3. (C) The temperature dependence of the junction resistance (RJ) between the Py and the 2DEG between SrTiO3 and 6-UC LaAlO3, and the 2DEG resistance (R2DEG).

  • Fig. 4 The temperature and LaAlO3 thickness dependences of IEE for the Rashba-split 2DEGs for SrTiO3/LaAlO3 with thickness up to 40 UC.

    (A and B) The temperature dependence of VIEE of the Rashba-split 2DEGs for SrTiO3/20-UC LaAlO3 and SrTiO3/40-UC LaAlO3, respectively. Inset: Temperature dependence of RJ between the Py and the 2DEG between SrTiO3 and LaAlO3. (C) The normalized V*IEE as a function of the LaAlO3 thickness.

  • Fig. 5 The gate voltage dependence of IEE of the Rashba-split 2DEG between SrTiO3 and 3-UC LaAlO3.

    (A) The measured voltage on SrTiO3/3-UC LaAlO3 as a function of the magnetic field at 300 K for Vg = −20, −6, 0, 100, and 200 V. Inset: Schematic of the measurement under electric field using the SrTiO3 as the dielectric layer. (B) The gate voltage dependence of VIEE of the Rashba-split 2DEG between SrTiO3 and 3-UC LaAlO3. (C) The gate voltage dependence of 2DEG resistance between SrTiO3 and 3-UC LaAlO3.

Supplementary Materials

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. The electron transport properties of the 2DEG.
    • fig. S2. The gate voltage dependence of IEE of the Rashba-split 2DEG between SrTiO3 and 3-UC LaAlO3.

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