Accumulation, inversion, and depletion layers in SrTiO3

作者：Reich K V^*; Schecter M; Shklovskii B I

来源：Physical Review B, 2015, 91(11): 115303.

DOI：10.1103/PhysRevB.91.115303

We study potential and electron density depth profiles in accumulation, inversion, and depletion layers in crystals with a large and nonlinear dielectric response such as SrTiO3. We describe the lattice dielectric response using the Landau-Ginzburg free energy expansion. In accumulation and inversion layerswe arrive at newnonlinear dependencies of the width d of the electron gas on an applied electric field D-0. Particularly important is the predicted electron density profile of accumulation layers (including the LaAlO3/SrTiO3 interface) n(x) proportional to (x + d)(-12/7), where d proportional to D-0(-7/5) . We compare this profile with available data and find satisfactory agreement. For a depletion layer we find an unconventional nonlinear dependence of the capacitance on voltage. We also evaluate the role of spatial dispersion in the dielectric response by adding a gradient term to the Landau-Ginzburg free energy.

• 出版日期2015-3-6