Kumar, Pramod and Dogra, Anjana and Bhadauria, P. P. S. and Gupta, Anurag and Maurya, K. K. and Budhani, R. C. (2015) Enhanced spin-orbit coupling and charge carrier density suppression in LaAl1-xCrxO3/SrTiO3 hetero-interfaces. Journal of Physics: Condensed Matter, 27 (12). ISSN 0953-8984

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We report a gradual suppression of the two-dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 interface on substitution of chromium at the Al sites. The sheet carrier density at the interface (n(square)) drops monotonically from similar to 2.2 x 10(14) cm(-2) to similar to 2.5 x 10(13) cm(-2) on replacing approximate to 60% of the Al sites by Cr and the sheet resistance (R-square) exceeds the quantum limit for localization (h/2e(2)) in the concentrating range 40-60% of Cr. The samples with Cr <= 40% show a distinct minimum (T-m) in metallic R-square (T) whose position shifts to higher temperatures on increasing the substitution. Distinct signatures of Rashba spin-orbit interaction (SOI) induced magnetoresistance (MR) are seen in R-square measured in out of plane field (H-perpendicular to) geometry at T <= 8K. Analysis of these data in the framework of Maekawa-Fukuyama theory allows extraction of the SOI critical field (H-SO) and time scale (tau(SO)) whose evolution with Cr concentration is similar as with the increasing negative gate voltage in LAO/STO interface. The MR in the temperature range 8K <= T <= T-m is quadratic in the field with a +ve sign for H-perpendicular to and -ve sign for H-parallel to. The behaviour of H-parallel to MR is consistent with Kondo theory which in the present case is renormalized by the strong Rashba SOI atT < 8K.

Item Type: Article
Uncontrolled Keywords: oxide hetero-structures, 2DEG, magnetoresistance
Subjects: Applied Physics/Condensed Matter
Depositing User: Dr. Rajpal Walke
Date Deposited: 23 Sep 2016 04:50
Last Modified: 23 Sep 2016 04:50
URI: http://npl.csircentral.net/id/eprint/1809

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