ESPCI web site
Jeudi 14 Novmebre 2013, 14h
Amphi Holweck, Esc C, 1ème etage
Life beyond <001> : reshaping 2DEGS at the LaAlO3/SrTiO3 interface by crystal orientation
Gervasi Herranz
Institut de Ciència de Materials de Barcelona ICMAB-CSIC, Campus de la UAB,
08193 Bellaterra, Catalonia, Spain
About tens years ago, a high-mobility two-dimensional gas (2DEG) was discovered at the interface between two wide-bandgap insulators : SrTiO3 (STO) and LaAlO3 (LAO) [1]. Later on, superconductivity below a few hundreds of mK as well as traces of magnetism were also reported, making the LAO/STO interface one of the most intriguing electron systems in the condensed matter area. Nevertheless, until very recently, all the research was univocally directed to the (001)-oriented interface, along which a built-in electrostatic potential is generally thought to generate the 2DEGs. Last year, however, high-mobility 2DEGs have been discovered also along other directions, including <110> for which such a built-in potential was unexpected [2,3]. Here I will give an overview of the 2DEG properties of the <001>, <110> and <111> 2DEGs at the LAO/STO interface. The different crystal orientations reshape the 2DEG electron structure and, in turn, their electronic properties. In particular, finding 2D-superconductivity at different crystal orientations has given us an unparalleled opportunity to scrutinize the effects of orbital and electronic reconstructions driven by the variation of crystallographic orientations. Our results point to a larger extension of the electron system at the (110)-interface [4], opening up fascinating questions, e.g., how are the coexistence of magnetism and superconductivity or the Rashba spin-orbit coupling affected by the reorganized electronic hierarchy.
[1] Ohtomo, A. & Hwang. Nature 427, 423–426 (2004).
[2] G. Herranz et al., Scientific Reports 2 758 (2012)
[3] A. Annadi et al., Nature Communications 4, 1838 (2013)
[4] G. Herranz et al., submitted, arXiv:1305.2411 [cond-mat.str-el].