Effect of Growth Conditions on the Formation of a 2-Dimensional Electron Gas at Antiferromagnetic LaCrO3 /SrTiO3 Interfaces*

The realization of a high mobility two-dimensional conducting interface between a polar anti-ferromagnet, LaCrO3 (LCO) and non-polar SrTiO3 (STO) has important implications for the interfacial coupling of electronic and magnetic degrees of freedom. To realize such an interface, we examine the effect of growth conditions and post growth treatment on the structural and electronic properties of the polar/non-polar(LCO/STO) interfaces. Growth at high temperatures and low oxygen partial pressure followed by post growth annealing in Oxygen results in a 2-dimensional electron gas(2-deg) at the interface. The dimensionality of the conducting layer is confirmed by electric and magneto transport measurements. Growth at a lower temperature or higher partial oxygen pressure leads to an insulating interface. High-resolution synchrotron X-ray-based structural determination of the atomic-scale structures of both metallic and insulating LCO/STO interfaces shows structural differences between the two cases attributed to competing mechanisms present to alleviate the interfacial polar discontinuity.