Orbital Symmetry and Electronic Properties of Two-Dimensional Electron Systems in Oxide Heterointerfaces

Semi-empirical approaches suffice to derive the basic features of the electronic band structure for the cubic phase of SrTiO₃. The remarkable tunability of the two-dimensional superconductivity and Rashba spin–orbit fields is intimately related to the electronic band structure of the two-dimensional electron systems (2DES). The transport and electronic properties of the LaAlO₃/SrTiO₃ interfaces depend dramatically on its atomic chemical composition. The chapter shows that the crystal orientation of the interface modifies the electronic subband structure of the 2DESs as well as their physical properties. Crystal symmetry enabled the realization of different 2DES band reconstructions, thus allowing a selective occupancy of states of different symmetry. The relevance of spin–orbit coupling is a consequence of the large confinement of the 2DESs, which breaks the inversion symmetry, and induces a Rashba spin–orbit field. The large Rashba term has prompted suggestions about the promotion of unconventional superconductive states.