Compositional and temperature evolution of crystal structure of new thermoelectric compound LaOBiS2-xSex

Abstract

We examined the crystal structure of the new thermoelectric material LaOBiS2-xSex, whose thermoelectric performance is enhanced by Se substitution, by using powder synchrotron X-ray diffraction and Rietveld refinement. The emergence of metallic conductivity and enhancement of the thermoelectric power factor of LaOBiS2-xSex can be explained with the higher in-plane chemical pressure caused by the increase of Se concentration at the in-plane Ch1 site (Ch = S, Se). High-temperature X-ray diffraction measurements for optimally substituted LaOBiSSe revealed anomalously large atomic displacement parameters (Uiso) for Bi and Ch atoms in the BiCh2 conduction layers. The anisotropic analysis of the atomic displacement parameters (U11 and U33) for the in-plane Bi and Ch1 sites suggested that Bi atoms exhibit large atomic displacement along the c-axis direction above 300 K, which could be the origin of the low thermal conductivity in LaOBiSSe. The large Bi vibration along the c-axis direction could be related to in-plane rattling, which is a new strategy for attaining low thermal conductivity and phonon-glass-electron-crystal states.

arXiv comment25 pages, 5 figures, 3 supplemental materials, version accepted in JAP

References in corpus (15)

• Superconductivity in novel BiS2-based layered superconductor LaO1-xFxBiS2
• Novel BiS2-based layered superconductor Bi4O4S3
• Minimal electronic models for superconducting BiS${}_2$ layers
• In-plane chemical pressure essential for superconductivity in BiCh2-based (Ch: S, Se) layered structure
• Pairing with dominant triplet component and possible weak topological superconductivity in BiS${}_2$-based superconductors
• Unexpected Giant Superconducting Fluctuation and Anomalous Semiconducting Normal State in NdO1-xFxBi1-yS2 Single Crystals
• In-plane Charge Fluctuations in Bismuth Sulfide Superconductors
• Enhancement of thermoelectric properties by Se substitution in layered bismuth-chalcogenide LaOBiS2-xSex
• High thermoelectric performance and low thermal conductivity of densified LaOBiSSe
• Site Selectivity on Chalcogen Atoms in Superconducting La(O,F)BiSSe
• Structures and Optical Absorption of Bi2OS2 and LaOBiS2
• High-temperature thermoelectric properties of novel layered bismuth-sulfide LaO1-xFxBiS2
• Testing the $d_{x^2-y^2}^{\ast }$-wave pairing symmetry by quasiparticle interference in BiS${}_2$-based superconductors
• Electrical and Thermal Transport of Layered Bismuth-chalcogenide EuBiS2F at temperatures between 300 and 623 K
• Giant birefringence in layered compound LaOBiS2

Cited by in corpus (10)

• Material Development and Physical Properties of BiS2-Based Layered Compounds
• Intrinsic Phase Diagram of Superconductivity in the BiCh2-based System Without In-plane Disorder
• Superconductivity and its Enhancement under High Pressure in "F-free" Single Crystals of CeOBiS${}_2$
• Electronic Origins of Large Thermoelectric Power Factor of LaOBiS2-xSex
• Crystal structure, site selectivity, and electronic structure of layered chalcogenide LaOBiPbS3
• Prediction of the High Thermoelectric Performance of Pnictogen Dichalcogenide Layered Compounds with Quasi-One-Dimensional Gapped Dirac-like Band Dispersion
• Superconductivity of high-entropy-alloy-type transition-metal zirconide (Fe,Co,Ni,Cu,Ga)Zr2
• Pressure induced quenching of planar rattling in Cu${}_{10}$Zn${}_2$Sb${}_4$S${}_{13}$ studied by specific-heat and x-ray diffraction measurements
• Enhanced thermoelectricity by controlled local structure in bismuth-chalcogenides
• Bulk superconductivity induced by Se substitution in self-doped BiCh2-based compound CeOBiS2-xSex