High-mobility two-dimensional electron gas at the PbZr 0.5 Ti 0.5 O 3 /BaSnO 3 heterostructure

The two-dimensional electron gas (2DEG) formed at the oxide heterointerface between LaAlO 3 (LAO) and SrTiO 3 (STO) has gained significant attention due to its exotic physical properties and interfacial conductivity. However, the 2DEG resides in a weakly dispersive Ti-d band, resulting in relatively low mobility. This limitation hampers its practical applications in future oxide electronics. To enhance the mobility of the 2DEG, we propose the use of BaSnO 3 (BSO) as a novel host material with a highly dispersive conduction Sn-5 s band. The s orbitals in BSO are significantly more delocalized than d orbitals, leading to a higher dispersion of the conduction band. Our first-principles density functional theory (DFT) calculations reveal that a high-mobility n-type 2DEG can indeed be formed near the PbZr 0.5 Ti 0.5 O 3 /BSO interface. The polar field of the ferroelectric PbZr 0.5 Ti 0.5 O 3 generates an interfacial conducting state in BSO, resulting in a high-mobility n-type 2DEG within the highly dispersive Sn-5 s band.