Researchers at India's Institute of Nano Science and Technology (INST), an autonomous research institution of Department of Science and Technology (DST), recently produced a transparent conducting interface between two insulating materials with room temperature spin polarized electron gas, which allows for see-through devices with efficient spin currents.
Prof. Suvankar Chakraverty and his group at INST have produced a 2D Electron Gas (2DEG) with room temperature spin polarization at the interface composed of chemicals LaFeO3 and SrTiO3. They grew super lattices and hetero structures of oxide materials to realize new and exotic two-dimensional electron gas at the interface of two insulating oxides that could be useful for next generation quantum devices.
The team's conducting interface in LaFeO3 (LFO)-SrTiO3 (STO) demonstrates spin-polarization signatures, namely, negative magnetoresistance (MR) and anomalous Hall resistivity >150 K and even up to room temperature. However, the same system showed positive MR and normal Hall effect at temperatures <150 K.
From density functional theory calculations, the team found that this is related to the structural transition of the substrate, amplified here as the changes happen at the interface.
This leads to a net spin polarization of the interface states at the Fermi energy in the high-temperature phase, allowing for an anomalous Hall effect and negative MR.
In addition, this interface appears to be almost transparent in the entire range of visible light. The team's observation might be viewed as a step toward room-temperature transparent oxide spintronics.
The research was supported by a grant from the DST-Nanomission and Board of Research in Nuclear Sciences (BRNS) in the form of a sophisticated, custom-made instrument called a combinatorial pulsed laser deposition setup.