Dresden 2020 – wissenschaftliches Programm
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MA 3.9: Vortrag
Montag, 16. März 2020, 11:45–12:00, HSZ 201
Charge transport in oxygen-deficient EuTiO3: The emerging picture of dilute metallicity in quantum-paraelectric perovskite oxides — •Johannes Engelmayer1, Xiao Lin1, Christoph Grams1, Raphael German1, Tobias Fröhlich1, Joachim Hemberger1, Kamran Behnia2, and Thomas Lorenz1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Laboratoire Physique et Etude de Matériaux, PSL Research University, 75005 Paris, France
Quantum paraelectric SrTiO3 is a large-gap band insulator that becomes metallic upon electron doping already at extremely small charge-carrier concentrations ≃ 5× 1017cm−3. The observed T2 resistivity in this material challenges conventional theories for electron–electron scattering.
We report on a study of charge transport in the related compound EuTiO3 where the carrier density is tuned via reduction.
Because of a lower electric permittivity, the metal–insulator transition (MIT) in EuTiO3−δ occurs at higher carrier densities compared to doped SrTiO3. The critical carrier concentration nc for the MIT is discussed in the context of the so-called Mott criterion and compared with other doped perovskite compounds with a quantum-paraelectric parent.
Similar to doped SrTiO3, EuTiO3−δ shows a distinct AT2 resistivity, where the prefactor A scales with n. Using a simple three-band model, the A(n) behavior in doped perovskite titanates can be described over a large range of n.
Funded by DFG via CRC1238 and via ANR-DFG LO 818/6-1 and HE 3219/6-1.