Vacancy induced metallicity at the CaHfO_3/SrTiO_3 interface

摘要

Density functional theory is used to study the electronic properties of the oxide heterointerface CaHfO_3/SrTiO_3. Structural relaxation is carried out with and without O vacancies. As compared to related interfaces, strongly reduced octahedral distortions are found. Stoichiometric interfaces between the wide band gap insulators CaHfO_3 and SrTiO_3 turn out to exhibit an insulating state. However, interface metallicity is introduced by O vacancies, in agreement with experiment. The reduced octahedral distortions and necessity of O deficiency indicate a less complicated mechanism for the creation of the interfacial electron gas.