1303.6216 (D. Yazici et al.)

Superconductivity induced by electron doping in the system La1-xMxOBiS2
(M = Ti, Zr, Hf, Th)    [PDF]

D. Yazici, K. Huang, B. D. White, I. Jeon, V. W. Burnett, A. J. Friedman, I. K. Lum, M. Nallaiyan, S. Spagna, M. B. Maple

We report a strategy to induce superconductivity in the BiS$_2$-based compound LaOBiS$_2$. Instead of substituting F for O, we increase the charge-carrier density (electron dope) via substitution of tetravalent Th$^{+4}$, Hf$^{+4}$, Zr$^{+4}$, and Ti$^{+4}$ for trivalent La$^{+3}$. It is found that both the LaOBiS$_2$ and ThOBiS$_2$ parent compounds are bad metals and that superconductivity is induced by electron doping with \emph{T$_c$} values of up to 2.85 K. The superconducting and normal states were characterized by electrical resistivity, magnetic susceptibility, and heat capacity measurements. We also demonstrate that reducing the charge-carrier density (hole doping) via substitution of divalent Sr$^{+2}$ for La$^{+3}$ does not induce superconductivity.

View original: http://arxiv.org/abs/1303.6216