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arXiv · 1504.03507

Electron degeneracy and intrinsic magnetic properties of epitaxial Nb:SrTiO$_3$ thin-films controlled by defects

A. Sarantopoulos·E. Ferreiro-Vila·V. Pardo·C. Magen·M. H. Aguirre·F. Rivadulla
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Abstract

We report thermoelectric power experiments in e-doped thin films of SrTiO$_3$ (STO) which demonstrate that the electronic band degeneracy can be lifted through defect management during growth. We show that even small amounts of cationic vacancies, combined with epitaxial stress, produce a homogeneous tetragonal distortion of the films, resulting in a Kondo-like resistance upturn at low temperature, large anisotropic magnetoresistance, and non-linear Hall effect. Ab-initio calculations confirm a different occupation of each band depending on the degree of tetragonal distortion. The phenomenology reported in this paper for tetragonally distorted e-doped STO thin films, is similarto that observed in LaAlO$_3$/STO interfaces and magnetic STO quantum wells.

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A. Sarantopoulos, E. Ferreiro-Vila, V. Pardo, C. Magen, M. H. Aguirre, F. Rivadulla. 2015-04-14. Electron degeneracy and intrinsic magnetic properties of epitaxial Nb:SrTiO$_3$ thin-films controlled by defects. https://doi.org/10.1103/physrevlett.115.166801

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