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arXiv · 1408.1500

Magnetothermopower of $\delta$-doped LaTiO$_3$/SrTiO$_3$ interfaces in the Kondo regime

Shubhankar Das·P. C. Joshi·A. Rastogi·Z. Hossain·R. C. Budhani
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Abstract

Measurements of magneto-thermopower (S(H, T)) of interfacial delta doped LaTiO$_3$/SrTiO$_3$ (LTO/STO) heterostructure by an iso-structural antiferromagnetic perovskite LaCrO$_3$ are reported. The thermoelectric power of the pure LTO/STO interface at 300 K is $\approx$ 118 $\mu$V/K, but increases dramatically on $\delta$-doping. The observed linear temperature dependence of S(T) over the temperature range 100 K 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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Shubhankar Das, P. C. Joshi, A. Rastogi, Z. Hossain, R. C. Budhani. 2014-08-07. Magnetothermopower of $\delta$-doped LaTiO$_3$/SrTiO$_3$ interfaces in the Kondo regime. https://doi.org/10.1103/physrevb.90.075133

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