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

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).

6 pages, 4 figures, Accepted in Phys. Rev. B

References in corpus (2)

• Magnetic effects at the interface between nonmagnetic oxides
• Electronic properties of buried hetero-interfaces of LaAlO3 on SrTiO3

Cited by in corpus (2)

• Signature of enhanced spin-orbit interaction in the magnetoresistance of LaTiO${}_3$/SrTiO${}_3$ interfaces on $\delta$-doping
• Engineered Kondo screening and nonzero Berry phase in SrTiO3/LaTiO3/SrTiO3 heterostructures