Spectroscopic evidence for competing reconstructions in polar multilayers LaAlO3/LaVO3/LaAlO3.
We have studied the valence redistribution of V in LaAlO(3)/LaVO(3)/LaAlO(3) trilayers, which are composed of only polar layers grown on SrTiO3 (001) substrates, by core-level photoemission spectroscopy. We have found that the V valence is intermediate between V3+ and V4+ for thin LaAlO3 cap layers, decreases with increasing cap-layer thickness, and finally recovers the bulk value of V3+ at approximately 10 unit-cell thickness. In order to interpret these results, we propose that the atomic reconstruction of the polar LaAlO3 surface competes with the purely electronic V valence change so that the polar catastrophe is avoided at the cost of minimum energy.
Takizawa
M
M
Department of Physics, University of Tokyo, 3-7-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
Hotta
Y
Y
Susaki
T
T
Ishida
Y
Y
Wadati
H
H
Takata
Y
Y
Horiba
K
K
Matsunami
M
M
Shin
S
S
Yabashi
M
M
Tamasaku
K
K
Nishino
Y
Y
Ishikawa
T
T
Fujimori
A
A
Hwang
H Y
HY