Direct Observation of an Incommensurate Charge Density Wave in the BiS2-based Superconductor NdO1-xFxBiS2

The nature of superconductivity in BiS$_2$-based superconductors has been controversial while ab-initio calculations proposed this system in close proximity to a charge-density-wave (CDW) phase. Using high-energy high-flux X-ray diffraction, we reveal an intrinsic and long-range CDW phase coexisting with superconductivity in NdO$_{1-x}$F$_{x}$BiS$_2$ superconductor ($x$ = 0.37 and 0.3). The CDW wavevector in NdO$_{0.63}$F$_{0.37}$BiS$_2$ correspond Q$_{\rm{CDW}}$ = (0.17, 0.17, 0.5) and is associated with transverse atomic displacements. Interestingly, this wavevector does not match theoretical expectations based on either phonon softening or Fermi surface nesting. In NdO$_{0.7}$F$_{0.3}$BiS$_2$, where the superconducting transition temperature is highest, the CDW satellites are slightly broader and weaker compared to NdO$_{0.63}$F$_{0.37}$BiS$_2$, possibly suggesting the competition with the superconductivity. Lastly, we measure a thermal diffuse scattering across the superconducting transition temperature and find no meaningful changes in favor of the unconventional pairing mechanism. Our result suggests the importance of understanding CDW which might hold a key to the superconductivity in the BiS$_2$-based superconductor.Comment: 7 pages, 3 figures, Supplementary to be uploade

Cross-breed comparisons identified a critical 591-kb region for bovine carcass weight QTL (CW-2) on chromosome 6 and the Ile-442-Met substitution in NCAPG as a positional candidate

<p>Abstract</p> <p>Background</p> <p>Growth-related traits have been mapped on bovine chromosome 6 (BTA 6) in various bovine breed populations. We previously mapped a significant quantitative trait locus (QTL) for carcass and body weight (<it>CW-2</it>) between 38 and 55 cM on BTA 6 using a Japanese Black half-sib family. Additional QTL mapping studies detected four QTL for body or carcass weight that overlapped with <it>CW-2 </it>in Japanese Black and Japanese Brown half-sib families. To map the region in greater detail, we applied cross-breed comparisons of haplotypes that have been shown to be powerful in canine.</p> <p>Results</p> <p>We used 38 microsatellite markers to search for a shared <it>Q </it>(increasing carcass and/or body weight) haplotype within the 17-cM <it>CW-2 </it>region among five sires. Linkage disequilibrium mapping using maternal alleles of the offspring showed that an 815-kb shared <it>Q </it>haplotype was associated with body or carcass weight in both breeds. The addition of 43 single nucleotide polymorphism (SNP) markers narrowed the region to 591 kb containing 4 genes. The SNP changing Ile-442 to Met in <it>NCAPG </it>(chromosome condensation protein G) was significantly associated with carcass weight (<it>p </it>< 1.2 × 10^-11) in a large Japanese Black population as well as in the five families. The <it>Q </it>allele of the SNP was also associated with a larger longissimus muscle area and thinner subcutaneous fat thickness in steers of all five families, indicating that the <it>CW-2 </it>locus is pleiotropic and favorable for marker-assisted selection of beef cattle.</p> <p>Conclusion</p> <p>A 591-kb critical region for <it>CW-2 </it>was identified. The SNP changing Ile-442 to Met in <it>NCAPG </it>(chromosome condensation protein G) can be used as a positional candidate of <it>CW-2 </it>for marker-assisted selection.</p

Superconductivity in oxygen-annealed FeTe1-xSx single crystal

We investigated the S-doping-driven phase transition from antiferromagnetic to superconducting in FeTe1-xSx single crystals. The partial substitution of Te by S suppresses antiferromagnetism in Fe-square lattice. Superconductivity is induced by oxygen annealing for only FeTe1-xSx in which the long-range magnetic ordering is suppressed. To realize superconductivity in FeTe1-xSx, both S concentration enough to suppress antiferromagnetism and oxygen annealing are required. Anisotropy of superconductivity in oxygen-annealed FeTe0.886S0.114 was estimated to be 1.17.Comment: 14 pages, 7 figure