First-principles study on electronic properties in BiFeO3 based heterostructures

Abstract

BiFeO3/SrTiO3(001) and BiFeO3/PbTiO3(001) heterostructures(HS) are investigated with two types of interfaces. Recently, using density functional theory (DFT) based firstprinciple calculations, evidence of half-metallicity is observed in a bulk tetragonal phase of BiFeO3(TBFO). The same structure exhibits half-metallicity along with two-dimensional hole gas (2DHG) on the TBFO(001) surface as well.In this work, two types of TBFO based heterostructures are studied as mentioned above in order to examine the persistence of half-metallicity in these perovskite based heterostructure systems. In case of BiFeO3/SrTiO3(001) (TBFO/STO) HS the (FeO2) −/ (SrO) 0 , and (BiO) +/(TiO2) 0 interfaces are investigated respectively.For BiFeO3/PbTiO3(001) (TBFO/PTO) HS the (FeO2) −/(PbO) 0 , and (BiO) +/ (TiO2) 0 interfaces are studied. A tiny amount of half-metallicity(Hmfm) appeared in the (FeO2) − / (SrO) 0 interface while (BiO) + /(TiO2) 0 interface contributes to metallicity in case of TBFO/ STO interface.Interestingly, (FeO2) − /(PbO) 0 interface turns out to be a distinct half-metal with hole-type charge carriers and (BiO) +/(TiO2) 0 behave as two-dimensional electron gas (2DEG) in case of TBFO/PTO HS.