Role of the local structure in superconductivity of LaO0.5F0.5BiS2-x Se x system

E Paris; Y Mizuguchi; M Y Hacisalihoglu; T Hiroi; B Joseph; G Aquilanti; O Miura; T Mizokawa; N L Saini

doi:10.1088/1361-648X/aa5e97

Role of the local structure in superconductivity of LaO_0.5F_0.5BiS_2-x Se _x system

J Phys Condens Matter. 2017 Apr 12;29(14):145603. doi: 10.1088/1361-648X/aa5e97. Epub 2017 Feb 6.

Authors

E Paris¹, Y Mizuguchi, M Y Hacisalihoglu, T Hiroi, B Joseph, G Aquilanti, O Miura, T Mizokawa, N L Saini

Affiliation

¹ Dipartimento di Fisica, Università di Roma 'La Sapienza', P. le Aldo Moro 2, 00185 Roma, Italy. Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, V. le Regina Elena 291, 00185 Rome, Italy.

PMID: 28165329
DOI: 10.1088/1361-648X/aa5e97

Abstract

We have studied the local structure of LaO_0.5F_0.5BiS_2-x Se _x by Bi L₁-edge extended x-ray absorption fine structure (EXAFS). We find a significant effect of Se substitution on the local atomic correlations with a gradual elongation of average in-plane Bi-S bondlength. The associated mean square relative displacement, measuring average local distortions in the BiS₂ plane, hardly shows any change for small Se substitution, but decreases significantly for [Formula: see text]. The Se substitution appears to suppress the local distortions within the BiS₂ plane that may optimize in-plane orbital hybridization and hence the superconductivity. The results suggest that the local structure of the BiS₂-layer is one of the key ingredients to control the physical properties of the BiS₂-based dichalcogenides.