New Member of BiS₂-Based Superconductor NdO_1-xF_xBiS₂

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

“…[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 Superconductivity in LnO 1-x F x BiS 2 with Ln = Ce, Pr, Nd and Yb also followed soon.…”

“…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. [18][19][20][21] Hole doping via alkali earthmetal-substitution at Ln-site did not yield superconductivity.…”

“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] .…”