Synthesis, crystal structure and properties of the new superconductors TaRuB and NbOsB. (29th September 2015)

• Record Type: Journal Article
• Authors: Zheng, Qiang; Gumeniuk, Roman; Rosner, Helge; Schnelle, Walter; Prots, Yurii; Burkhardt, Ulrich; Grin, Yuri; Leithe-Jasper, Andreas
• Is Part Of: Journal of physics. Volume 27:Number 41(2015)
• Publication Date: 2015-09-29
• Subjects: borides -- crystal structure -- superconductivity -- electronic structure; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/0953-8984/27/41/415701
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Two new ternary compounds TaRuB and NbOsB were synthesized by arc-melting and annealing at 1500–1850 °C. They crystallize in orthorhombic primitive structures with space group Pbam . Magnetic susceptibility, electrical resistivity, and specific heat measurements reveal bulk superconductivity for metallic TaRuB with a K. Electronic structure calculations by DFT methods show that 4 d and 5 d transition-metal states dominate the density of states (DOS) at the Fermi level with a pronounced quasi one-dimensional behaviour along the [0 0 1] direction. Comparison of the calculated DOS at with specific heat data reveals a moderate electron–phonon coupling. Possible small boron vacancies could significantly reduce the DOS at, hence decrease for samples annealed at higher temperatures. For NbOsB, the DOS( ) is strongly reduced due to an increase of covalent bonding interactions between Os and B. Accordingly, a lower K is observed.