The potential profile at the LaAlO3/SrTiO3 (001) heterointerface in   operando conditions
  We report measurements of the gate-bias dependent band alignment, especially the confining potential profile, at the conducting LaAlO3/SrTiO3 (001) heterointerface using soft and hard x-ray photoemission spectroscopy. Depth-profiling analysis reveals that a significant potential drop on the SrTiO3 side of the interface occurs within ~2 nm of the interface under negative gate bias voltage. These results demonstrate gate control of the collapse of permittivity at the interface, and explain the dramatic loss of electron mobility with back-gate depletion. 
M. Minohara, Y. Hikita, C. Bell, H. Inoue, M. Hosoda, H. K. Sato, H.   Kumigashira, M. Oshima, E. Ikenaga, and H. Y. Hwang
cond-mat.mtrl-sci