Design of two-dimensional electron gas systems via polarization discontinuity from large-scale first-principles calculations

A two-dimensional electron gas (2DEG) formed at the interface between two insulating perovskite oxides has provided a versatile playground to explore emergent interfacial electronic and magnetic properties. Here we show that by using high-throughput first-principles calculations and a group of effective materials descriptors based on bulk perovskite materials, we are able to rapidly design more than 300 candidate 2DEG systems based on nonpolar/nonpolar perovskite heterostructures (HS). These HS are built from 34 nonpolar piezoelectric perovskite oxides that can show polarization behavior under epitaxial compressive strain and can be further divided into six groups of materials based on B-site elements: Ti-, Zr-, Hf-, Si-, Ge-, and Sn-based oxides. By taking one compound as the substrate from each group and building all the possible HS with an appropriate lattice mismatch 0 < f < 6%, we have carried out comprehensive first-principles calculations to verify the formation of the 2DEG in these HS. It has been found that a stable polarization and interfacial 2DEG exist in most of the selected HS. This work demonstrates an efficient way to perform high-throughput design of perovskite-oxide-based functional materials.