Theoretical analysis of the inverse Edelstein effect at the LaAlO₃/SrTiO₃ interface with an effective tight-binding model. Important role of the second d_xy subband

The two-dimensional electron gas formed at interfaces between SrTiO₃ and other materials has attracted much attention since extremely efficient spin-to-charge current conversion has been recently observed at these interfaces. This has been attributed to their complicated quantized multi-orbital structures with a topological feature. However, there are few reports quantitatively comparing the conversion efficiency values between experiments and theoretical calculations at these interfaces. In this study, we theoretically explain the experimental temperature dependence of the spin-to-charge current conversion efficiency using an 8 x 8 effective tight-binding model considering the second d_xy subband, revealing the vital role of the quantization of the multi-band structure. (author)