Role of the local structure in superconductivity of LaO0.5F0.5BiS2-xSexsystem.
We have studied the local structure of LaO0.5F0.5BiS2-xSexby 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 BiS2plane, 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 BiS2plane 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.
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.
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E
Paris
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Mizuguchi
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MY
Hacisalihoglu
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Hiroi
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Joseph
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Aquilanti
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Miura
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Mizokawa
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Saini