Phase separation and long-wavelength charge instabilities in spin-orbit coupled systems. (21st January 2015)

• Record Type: Journal Article
• Authors: Seibold, G.; Bucheli, D.; Caprara, S.; Grilli, M.
• Is Part Of: Europhysics letters. Volume 109:Number 1(2015:Jan.)
• Publication Date: 2015-01-21
• Subjects: 71.70.Ej -- 73.43.Nq -- 73.20.-r; Physics -- Periodicals; Electronic journals; 530.05
• DOI: 10.1209/0295-5075/109/17006
• Languages: English
• ISSNs: 0295-5075

Abstract

Abstract: We investigate a two-dimensional electron model with Rashba spin-orbit interaction where the coupling constant depends on the electronic density. It is shown that this dependence may drive the system unstable towards a long-wavelength charge density wave (CDW) where the associated second-order instability occurs in close vicinity to global phase separation. For very low electron densities the CDW instability is nesting-induced and the modulation follows the Fermi momentum k F . At higher density the instability criterion becomes independent of k F and the system may become unstable in a broad momentum range. Finally, upon filling the upper spin-orbit split band, finite momentum instabilities disappear in favor of phase separation alone. We discuss our results with regard to the inhomogeneous phases observed at the LaAlO3 /SrTiO3 or LaTiO3 /SrTiO3 interfaces.