Sergio Caprara, Dipartimento di Fisica, Sapienza Università di Roma

Lundi 24 Mars 2014, 16h
Amphi Holweck, Esc C, 1ème etage

Inhomogeneous superconductivity in oxide heterostructures with strong
Rashba spin-orbit interaction

Sergio Caprara
Dipartimento di Fisica, Sapienza Università di Roma

The peculiar “tailish” resistance of the LaAlO3/SrTiO3 (LAO/STO) or
LaTiO3/SrTiO3 (LTO/STO) heterostructures is due to 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], yielding a percolative character of the transition to the zero
resistance state [2].

To explain the systematic occurrence of mesoscopic superconducting domains,we model the electron gas at the interface of these oxide heterostructures considering a two-dimensional electron gas in the presence of a sizable Rashba spin-orbit interaction (RSOI). Under simple general assumptions, we show that an electronic phase separation occurs for realistic values of the RSOC and of
the band parameters [3]. This could provide an intrinsic mechanism for the recently observed inhomogeneous phases at the LAO/STO or LTO/STO interfaces and open the way to new interpretations of the quantum critical behavior of LTO/STO [4,5,6]. 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
[6,7].

[1] D. Bucheli, S. Caprara, C. Castellani, and M. Grilli, New Journal of Physics 15, 023014 (2013).
[2] S. Caprara, J. Biscaras, N. Bergeal, D. Bucheli, S. Hurand, C. Feuillet-Palma, A. Rastogi, R. C. Budhani, J. Lesueur, and M. Grilli, Physical Review B 88, 020504(R) (2013).
[3] S. Caprara, F. Peronaci, and M. Grilli, Physical Review Letters 109, 196401 (2012).
[4] J. Biscaras, N. Bergeal, S. Hurand, C. Feuillet-Palma,A.Rastogi,
R. C. Budhani, M. Grilli, S.Caprara, and J. Lesueur, Nature Materials 12, 542 (2013).
[5] J. Biscaras, N. Bergeal, S. Hurand, C. Feuillet-Palma, A. Rastogi, R. C. Budhani, M. Grilli, S. Caprara, and J. Lesueur, Journal of Physics : Conference Series 449, 012035 (2013).
[6] S. CAPRARA, D. Bucheli, M. Grilli, J. Biscaras, N. Bergeal, S. Hurand, C. Feuillet-Palma, J. Lesueur, A. Rastogi, and R. C. Budhani, to appear in Spin (2014).
[7] D. Bucheli, M. Grilli, F. Peronaci, G. Seibold, and S. Caprara, in preparation.

Haut de page



À lire aussi...

Klaus Ensslin, ETH Zurich

Jeudi 20 Mars 2014, 14hAmphi Holweck, Esc C, 1ème etage Imaging of integer and fractional quantum Hall edge states Klaus Ensslin ETH Zurich (...) 

> Lire la suite...

R. L. Greene, Center for Nanophysics and Advanced Materials (CNAM), University of Maryland

Jeudi 03 July 2014, 14hAmphi Holweck, Esc C, 1ème etage Topological Surface States in the Kondo Insulator SmB6 ? R. L. GreeneCenter for (...) 

> Lire la suite...