k•p subband structure of the LaAlO3/SrTiO3 interface

Heterostructures made of transition metal oxides are new tailor-made materials which are attracting much attention. We have constructed a six-band k center dot p Hamiltonian and used it within the envelope function method to calculate the subband structure of a variety of LaAlO3/SrTiO3 heterostructures. By use of density functional calculations, we determine the k center dot p parameters describing the conduction band edge of SrTiO3: the three effective mass parameters L = 0.6104 eV angstrom(2), M = 9.73 eV angstrom(2), N = -1.616 eV angstrom(2), the spin orbit splitting Delta(SO) = 28.5 meV, and the low temperature tetragonal distortion energy splitting Delta(T) = 2.1 meV. For confined systems we find strongly anisotropic nonparabolic subbands. As an application we calculate bands, density of states, and magnetic energy levels and compare the results to Shubnikov-de Haas quantum oscillations observed in high magnetic fields. For typical heterostructures we find that electric field strength at the interface of F = 0.1 meV/A for a carrier density of 7.2 x 10(12) cm(-2) results in a subband structure that is similar to experimental results.