"Intrinsic charge instability in oxide heterostructures with Rashba spinorbit coupling"
<br>
<br>

A phenomenological analysis of resistance and diamagnetic response in the
LaAlO3/SrTiO3 or LaTiO3/SrTiO3 (LXO/STO) heterostructures suggests the
occurrence of a low-dimensional (e.g., filamentary or fractal) structure of the
superconducting cluster with small long-distance connectivity embedded in the
two-dimensional system [1,2]. To explain the systematic occurrence of such
mesoscopically disordered regions, we model the electron gas at the interface of
oxide heterostructures considering a twodimensional electron gas in the presence
of a sizable Rashba spin-orbit coupling (RSOC). Under simple general
assumptions, we show that an electronic phase separation occurs for realistic
values of the RSOC and of the band parameters [3,4]. This could provide an
intrinsic mechanism for the recently observed inhomogenous phases at the LAO/STO
or LTO/STO interfaces and opens the way to new interpretations of the quantum
critical behaviour of LTO/STO [5]. We investigate the effects of temperature and
magnetic field on the charge instability finding a novel type of quantum
critical point related to the vanishing of the critical temperature of the
electronic phase separation [4].
<br>
<br>
[1] D. Bucheli, S. Caprara, C. Castellani, and M. Grilli, New Journal of Physics
15, 023014 (2013).
<br>
[2] S. Caprara, J. Biscaras, N. Bergeal, D. Bucheli, S. Hurand, C. Feuillet-Palma, 
A. Rastogi, R. C. Budhani, J. Lesueur, and M. Grilli, Phys. Rev. B 88, 020504(R) (2013).
<br>
[3] S. Caprara, F. Peronaci, and M. Grilli, Physical Review Letters 109, 196401
(2012)
<br>
[4] D. Bucheli, M. Grilli, F. Peronaci, G. Seibold, and S. Caprara,
arXiv:1307.5427.
<br>
[5] J. Biscaras, N. Bergeal, S. Hurand, C. Feuillet-Palma, A.Rastogi, R. C.
Budhani, M. Grilli,
S.Caprara, J. Lesueur, arXiv:1209.6464, and Nature Materials 12, 542 (2013)