Crystal Structure, Lattice Vibrations,and Superconductivity of LaO1-xFxBiS2

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.87.205134· OSTI ID:1097475

Lee, Jooseop ^[1]; Stone, Matthew B ^[1]; Huq, Ashfia ^[1]; Yildrim, Tanner ^[2]; Ehlers, Georg ^[1]; Mizuguchi, Y ^[3]; Miura, O ^[4]; Takano, Y ^[3]; Demura, S ^[3]; Lee, Seung Hyun ^[1]

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1. ORNL
2. NIST Center for Neutron Research (NCRN), Gaithersburg, MD
3. National Institute for Materials Science, Tsukuba, Japan
4. Tokyo Metropolican University

Neutron scattering measurements have been performed on polycrystalline samples of the newly discovered layered superconductor LaO0:5F0:5BiS2, and its nonsuperconducting parent compound LaOBiS2. The crystal structures and vibrational modes have been examined. Upon F-doping, while the lattice contracts signicantly along c and expands slightly along a, the buckling of the BiS2 plane remains almost the same. In the inelastic measurements, a large dierence in the high energy phonon modes was observed upon F substitution. Alternatively, the low energy modes remain almost unchanged between non-superconducting and superconducting states either by F- doping or by cooling through the transition temperature. Using density functional perturbation theory we identify the phonon modes, and estimate the phonon density of states. We compare these calculations to the current measurements and other theoretical studies of this new superconducting material.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1097475
• Journal Information: Physical Review B, Vol. 87, Issue 20; ISSN 1098--0121
• Country of Publication: United States
• Language: English