Theory of the SrTiO3 Surface State Two-Dimensional Electron Gas

We present a theory of the quasi two-dimensional electron gas (2DEG) systems which appear near the surface of SrTiO$_3$ when a large external electric field attracts carriers to the surface. We find that non-linear and non-local screening by the strongly polarizable SrTiO$_3$ lattice plays an essential role in determining 2DEG properties. The electronic structure always includes weakly bound bulk-like bands that extend over many SrTiO$_3$ layers. At 2D carrier-densities exceeding $\sim 10^{14} {\rm cm}^{-2}$ tightly bound bands emerge that are confined within a few layers of the surface.Comment: 10 pages, 9 figures, 1 tabl

Inferring geometric constraints in human demonstrations

This paper presents an approach for inferring geometric constraints in human demonstrations. In our method, geometric constraint models are built to create representations of kinematic constraints such as fixed point, axial rotation, prismatic motion, planar motion and others across multiple degrees of freedom. Our method infers geometric constraints using both kinematic and force/torque information. The approach first fits all the constraint models using kinematic information and evaluates them individually using position, force and moment criteria. Our approach does not require information about the constraint type or contact geometry; it can determine both simultaneously. We present experimental evaluations using instrumented tongs that show how constraints can be robustly inferred in recordings of human demonstrations.Comment: 2nd Conference on Robot Learning (CoRL 2018). Accepted. 14 pages, 5 figure