Long‐Range Non‐Coulombic Coupling at the LaAlO3/SrTiO3 Interface

Abstract

AbstractThe LaAlO3/SrTiO3 interface hosts a plethora of gate‐tunable electronic phases. Gating of LaAlO3/SrTiO3 interfaces is usually assumed to occur electrostatically. However, increasing evidence suggests that non‐local interactions can influence and, in some cases, dominate the coupling between applied gate voltages and electronic properties. Here, quasi‐1D ballistic electron waveguides are sketched at the LaAlO3/SrTiO3 interface as a probe to understand how gate tunability varies as a function of spatial separation. Gate tunability measurements reveal the scaling law to be at odds with the pure electrostatic coupling observed in traditional semiconductor systems. The non‐Coulombic gating at the interface is attributed to a long‐range nanoelectromechanical coupling between the gate and electron waveguide, possibly mediated by the ferroelastic domains in SrTiO3. The long‐range interactions at the LaAlO3/SrTiO3 interface add unexpected richness and complexity to this correlated electron system.