Superconductivity in Novel BiS₂-Based Layered Superconductor LaO_1-xF_xBiS₂

Abstract

Layered superconductors have provided some interesting fields in condensed matter physics owing to the low dimensionality of their electronic states. For example, the high-T c (high transition temperature) cuprates and the Febased superconductors possess a layered crystal structure composed of a stacking of spacer (blocking) layers and conduction (superconducting) layers, CuO 2 planes or Fe-Anion layers. The spacer layers provide carriers to the conduction layers and induce exotic superconductivity. Recently, we have reported superconductivity in the novel BiS 2 -based layered compound Bi 4 O 4 S 3 . It was found that superconductivity of Bi 4 O 4 S 3 originates from the BiS 2 layers. The crystal structure is composed of a stacking of BiS 2 superconducting layers and the spacer layers, which resembles those of high-T c cuprate and the Fe-based superconductors. Here we report a discovery of a new type of BiS 2 -based layered superconductor LaO 1Àx F x BiS 2 , with a T c as high as 10.6 K.

Charge Fluctuations in the NdO1−xFxBiS2 Superconductors

“…The new phonon mediated BiS 2 superconductors, LnO 1−x F x BiS 2 (Ln=La, Ce, Nd, Pr and Yb) [1,2] and Bi 6 O 4 S 4 (SO 4 ) 1−x [3], have attracted considerable attention recently because of the interplay of spatial disorder, phonon anomalies and superconductivity. Charge carriers are introduced either by electron doping or by defects in the spacer layers that sandwich the BiS 2 superconducting planes.…”

Synthesis and Properties of SmO0.5F0.5BiS2 and Enhancement in Tc in La1–ySmyO0.5F0.5BiS2

“…This article follows from our work related to a recent class of superconductors, Bi 4 O 4 S 3 and LnOBiS 2 which have some structural similarity to the important LnOFeAs class of superconductors. [7][8][9][10] For example both these systems crystallize in the same space group (P4/nmm), they have layered structure with a charge reservoir layer (LnO) and a superconducting layer (BiS 2 , Fe-As), their parent phases are semiconducting or poorly conducting and, most importantly, they become superconducting upon electron-doping (doping F -for O 2-or a tetravalent ion for Ln). [9][10][11][12][13][14][15][16][17] Superconductivity by fluorine -doping in LaO 1-x F x BiS 2 was first reported by Mizuguchi et al (T c ~ 2.5 K) 9 ( T c ~10 K could be achieved by high pressure synthesis).…”

“…[9][10][11][12][13][14][15][16][17] Superconductivity by fluorine -doping in LaO 1-x F x BiS 2 was first reported by Mizuguchi et al (T c ~ 2.5 K) 9 ( T c ~10 K could be achieved by high pressure synthesis). 9 Superconductivity in LnO 1-x F x BiS 2 with Ln = Ce, Pr, Nd and Yb also followed soon. [10][11][12][13][14][15][16] T c is enhanced by chemical pressure [18][19][20] or external applied pressure [22][23][24][25][26][27] as observed for LnOFeAs 28 for example in LnO 1-x F x BiS 2 , a slight enhancement in T c has been reported by substituting Se at the S sites or by inter-mixing rare earth ions.…”

“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] .…”