2015/07/18 by Jun Zhou, Teguh Citra Asmara, Zhou, Jun +9
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.1507.05165
Physical Review B (accepted)
arxiv created 2015/07/18 · arxiv updated 2015/07/21
The mechanism responsible for the extraordinary interface conductivity of LaAlO3 on SrTiO3 and its insulator-metal transition remains controversial. Here, using density functional theory calculations, we establish a comprehensive and coherent picture that the interplay of electronic reconstructions, lattice distortions, and surface oxygen vacancies fully compensates the polarization potential divergence in LaAlO3/SrTiO3, explaining naturally the experimental observations under different conditions. While lattice distortions and a charge redistribution between LaO and AlO2 sub-layers play a dominant role in insulating state, a spontaneous appearance of 1/4 oxygen vacancies per AlO2 sub-layer at the LaAlO3 surface accompanied by 0.5e- charge-transfer into the interface is responsible for interface conductivity and the discontinuous transition in LaAlO3/SrTiO3. Our model also explain properties of LaAlO3/SrTiO3 prepared with different growth conditions.