Figure 1

The $({\mathrm{SrTiO}}_3{)}_n/({\mathrm{LaTiO}}_3{)}_1$ superlattice structure (a) with a monolayer of ${\mathrm{LaTiO}}_3$ embedded in bulk ${\mathrm{SrTiO}}_3$. The positively charged La sheet produces a wedge-shaped potential (b) following Gauss’s law. In the bottom part of (b), the dots denote the cell-averaged electrostatic potential $V(z)$ calculated from Eq. (1) with distance $z$ from the interface in units of the ${\mathrm{SrTiO}}_3$ monolayer thickness, while the solid V-shaped line is a fit corresponding to a uniformly charged sheet. The potential confines the stripped-off La ($d^1$) electrons in the interface region (c). The contours show the electron charge density, integrated between the conduction bottom and the Fermi energy, indicating the electron leakage into about three Ti layers on either side of the interface. The top part of (b) shows the electron density $n(z)$, which is integrated over a perovskite layer at the position $z$, with the solid line being a fit using the lowest-energy Airy function. These results were calculated within the LSDA. Contour values for (c) are ${\rho }_n={\rho }_0{10}^{n\delta }$, where ${\rho }_0=3.4\times {10}^{-3}e/{\AA }^3$, $\delta =0.31$, and $n$ labels the contours.Reuse & Permissions

Figure 2

Lowest eigenstates of the electron in the wedge-shaped potential well of a uniform sheet-charge density, obtained from Eq. (2), with length and energies in scaled units (see text).Reuse & Permissions

Figure 3

Energy- and atom-resolved DOS (from LSDA), indicating the rapid decay of the Ti charge [mostly Ti ($d$)] as one moves away from the La sheet. In fact, note that very little Ti conduction charge is visible in the figure for Ti layers beyond Ti1.Reuse & Permissions

Figure 4

The Fermi surface of $({\mathrm{SrTiO}}_3{)}_5/({\mathrm{LaTiO}}_3{)}_1$ shown in the surface Brillouin zone of the superlattice and its wave function character indicated in the lower right part of the figure (from LSDA).Reuse & Permissions

Figure 5

Magnetic moments of the Ti atoms indicating the magnetic transition region at the interface for $({\mathrm{SrTiO}}_3{)}_4/({\mathrm{LaTiO}}_3{)}_6$, calculated using the $\mathrm{LSDA}+\mathrm{U}$ method.Reuse & Permissions