Infrared spectroscopy of Cr and V doped Sb$_2$Te$_3$: dilute magnetic semiconductors

ORAL

Abstract

Temperature dependent optical reflectance measurements on well characterized samples of non-intentionally doped, Cr-doped and V-doped Sb$_2$Te$_3$ show that both the parent compound and the Cr-doped version are narrow-gap semiconductors (E$_g\approx 0.25$ eV) with a conventional Drude free carrier absorption. The carrier density increases slightly with decreasing temperature while the scattering rate increases quadratically with temperature which is a sign of optical phonon scattering. Vanadium doping introduces a change in the temperature dependence of the scattering rate as well as higher electrical resistivity than Cr-doped Sb$_2$Te$_3$. An analysis of the literature values of the saturation magnetization for $H\parallel c$ suggests that V is in a mixed valence state V$^{3+}$/V$^{4+}$.

*Work support by NSERC

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Authors

  • David Crandles

    • Department of Physics, Brock University, Canada
    • Brock University

  • Jason Manson

    • Department of Physics, Brock University, Canada

  • Anthony Madubuonu

    • Department of Physics, Brock University, Canada

  • Ctirad Uher

    • Department of Physics, University of Michigan, USA
    • Department of Physics, University of Michigan, Ann Arbor
    • University of Michigan
    • Department of Physics, University of Michigan

  • Petr Lostak

    • Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Czech Republic