Superconductivity induced by electron doping in La1−xMxOBiS2(

D. Yazici

¹

,

Kevin Huang

²

,

B. D. White

³

et al.

Abstract

We report a strategy to induce superconductivity in the BiS2-based compound LaOBiS2. 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 LaOBiS2 and ThOBiS2 parent compounds are bad metals and that superconductivity is induced by electron doping with Tc 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.

Electronic phase diagram in a new BiS2-based Sr1−xLaxFBiS2system

“…First, the parent compound of the former is a semiconductor [15] while the latter is a bad metal [12]. Second, by electron doping, the resistivity decreases with the doping concentration in Sr 1−x La x FBiS 2 , which is distinct from LnO 1−x F x BiS 2 [12] and La 1−x M x OBiS 2 (M=Ti, Zr, Hf, Th) systems [32], where resistivity shows the opposite trend with the electron concentration. Third, no metal to semiconductor transition/crossover has been observed in LnO 1−x F x BiS 2 and La 1−x M x OBiS 2 systems.…”

“Checkerboard Stripe” Electronic State on Cleaved Surface of NdO0.7F0.3BiS2 Probed by Scanning Tunneling Microscopy

“…The recent discovery of BiS 2 -based superconductors has triggered many research activities, because of (i) the structural similarity to cuprates and pnictides and (ii) their relatively high T c [19][20][21][22][23][24][25][26][27] . Recent theoretical calculations have suggested that a quasi-one-dimensional character of the band dispersion provides a good Fermi surface nesting [28][29][30][31][32] .…”

Unusual Mixed Valence of Eu in Two Materials—EuSr2Bi2S4F4 and Eu2SrBi2S4F4: Mössbauer and X-ray Photoemission Spectroscopy Investigations

“…Broadly categorising, these superconducting materials comprise the families Bi-O-S (Tc = 4.5-6 K) [1][2][3][4][5] , LnO1−xFxBiS2 (Ln = La, Ce, Pr, Nd, Sm and Yb) (Tc = 1.9-5.4 K) [6][7][8][9][10][11][12] , and Sr1−xLnxFBiS2 (Ln = La, Ce, Pr, Nd and Sm) (Tc ~ 3 K) [13][14][15][16][17] . The parent LnOBiS2 (Ln = La, Ce and Th) and SrFBiS2 compounds are semiconducting [18][19][20] . In these compounds, superconductivity is induced by doping them with suitable electron donors 6,13,16,17 .…”