%0 Journal Article
%A Gunkel, Felix
%A Waser, R.
%A Ramadan, Amr H. H.
%A De Souza, Roger A.
%A Hoffmann-Eifert, Susanne
%A Dittmann, Regina
%T Space charges and defect concentration profiles at complex oxide interfaces
%J Physical review / B
%V 93
%N 24
%@ 2469-9950
%C College Park, Md.
%I APS
%M FZJ-2016-03490
%P 245431
%D 2016
%X We discuss electronic and ionic defect concentration profiles at the conducting interface between the two wide-band-gap insulators LaAlO3 and SrTiO3 (STO). The profiles are deduced from a thermodynamic model considering a local space charge layer (SCL) originating from charge transfer to the interface region, thus combining electronic and ionic reconstruction mechanisms. We show that the electrical potential confining the two-dimensional electron gas (2DEG) at the interface modifies the equilibrium defect concentrations in the SCL. For the n-conducting interface, positively charged oxygen vacancies are depleted within the SCL, while negatively charged strontium vacancies accumulate. Charge compensation within the SCL is achieved by a mixed ionic-electronic interface reconstruction, while the competition between 2DEG and localized ionic defects is controlled by ambient pO2. The concentration of strontium vacancies increases drastically in oxidizing conditions and exhibits a steep depth profile towards the interface. Accounting for the low cation diffusivity in STO, we also discuss kinetic limitations of cation defect formation and the effect of a partial equilibration of the cation sublattice. We discuss the resulting implications for low temperature transport
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000378816000014
%R 10.1103/PhysRevB.93.245431
%U https://juser.fz-juelich.de/record/810924