Band Structure and Spin–Orbital Texture of the $(111)‐KTaO_{3}$ 2D Electron Gas

2D electron gases (2DEGs) in oxides show great potential for the discoveryof new physical phenomena and at the same time hold promise for electronicapplications. In this work, angle-resolved photoemission is used to determinethe electronic structure of a 2DEG stabilized in the (111)-oriented surface ofthe strong spin–orbit coupling material KTaO3. The measurements revealmultiple sub-bands that emerge as a consequence of quantum confinementand form a sixfold symmetric Fermi surface. This electronic structure is wellreproduced by self-consistent tight-binding supercell calculations. Based onthese calculations, the spin and orbital texture of the 2DEG is determined.It is found that the 2DEG Fermi surface is derived from bulk J = 3/2 statesand exhibits an unconventional anisotropic Rashba-like lifting of the spindegeneracy.Spin-momentum locking holds only for high-symmetry directionsand a strong out-of-plane spin component renders the spin texture threefoldsymmetric. It is found that the average spin-splitting on the Fermi surfaceis an order of magnitude larger than in SrTiO3, which should translateinto an enhancement in the spin–orbitronic response of (111)-KTaO3 2DEGbaseddevices