Strain‐Gradient‐Induced Modulation of Carrier Density and Mobility at the LaAlO 3 /SrTiO 3 Heterointerface

A strain gradient induced by mechanical bending on a SrTiO 3 substrate is demonstrated, and has a pronounced influence on the carrier density and mobility of the interfacial 2D electron gas at the LaAlO 3 /SrTiO 3 heterointerface. Tensile and compressive strain gradients represent two states of upward and downward bending. Under the tensile strain gradient, the carrier density decreases and the mobility has about 200% increase. Conversely, under the compressive strain gradient, the mobility decreases and the carrier density increases by up to 107%. These results demonstrate a range of opportunities to modulate the carrier density and mobility at oxide heterointerface and open up a promising way for further research on application of oxide devices.