Das, Shubhankar and Joshi, P. C. and Rastogi, A. and Hossain, Z. and Budhani, R. C.
(2014)
Magnetothermopower of delta-doped LaTiO3/SrTiO3 interfaces in the Kondo regime.
Physical Review B , 90 (7).
ISSN 1098-0121
Abstract
Measurements of magnetothermopower [S(H, T)] of interfacial delta-doped LaTiO3/SrTiO3 (LTO/STO) heterostructure by an isostructural antiferromagnetic perovskite LaCrO3 are reported. The thermoelectric power of the pure LTO/STO interface at 300 K is approximate to 118 mu V/K, but increases dramatically on delta doping. The observed linear temperature dependence of S(T) over the temperature range 100 to 300 K is in agreement with the theory of diffusion thermopower of a two-dimensional electron gas. The S(T) displays a distinct enhancement in the temperature range (T < 100 K) where the sheet resistance shows a Kondo-type minimum. We attributed this maximum in S(T) to Kondo scattering of conduction electron by localized impurity spins at the interface. The suppression of S by a magnetic field and the isotropic nature of the suppression in out-of-plane and in-plane field geometries further strengthen the Kondo-model-based interpretation of S(H,T).
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