Two-dimensional electron-gas-like charge transport at the interface between a magnetic Heusler alloy and SrTiO3

We report remarkably low residual resistivity, giant residual resistivity ratio, free-electron-like Hall resistivity, and high mobility (approximate to 10(4) cm(2) V-1 s(-1)) charge transport in epitaxial films of Co2MnSi and Co2FeSi grown on (001) SrTiO3. This unusual behavior is not observed in films deposited on other cubic oxide substrates of comparable lattice parameters. The scaling of the resistivity with thickness of the films allows the extraction of interface conductance, which can be attributed to a layer of oxygen vacancies confined within 1.9 nm of the interface as revealed by atomically resolved electron microscopy and spectroscopy. The high mobility transport observed here at the interface of a fully spin polarized metal is potentially important for spintronics applications.