Thermodynamic stability and superconductivity of tantalum carbides from first-principles cluster expansion and isotropic Eliashberg theoryShow others and affiliations
2022 (English)In: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 202, article id 111004Article in journal (Refereed) Published
Abstract [en]
The phase stability of tantalum carbides, particularly cubic rocksalt TaCx and hexagonal Ta2Cx, where 0 ≤ x ≤ 1 due to the presence of vacancies on the C sites, is explored using a first-principles cluster-expansion method. Our results demonstrate that at 0 K, in addition to stoichiometric cubic TaC and hexagonal Ta2C both widely known in the literature, carbon-deficient face-centered orthorhombic TaC0.833 is identified as a thermodynamically stable phase in the binary Ta-C system. By investigating their vibrational and electronic properties, the three carbides are dynamically stable and are metallic. We further demonstrate, by adopting phonon mediated superconductivity based on the Bardeen-Cooper-Schrieffer theory, that cubic TaC, face-centered orthorhombic TaC0.833, and hexagonal Ta2C superconduct, whose transition temperatures are estimated by the Allen-Dynes equation to be 10.0 K, 6.8 K, and 1.4 K, respectively. The physical origin of superconductivity in these stable carbides are discussed and described, based on the detailed analysis of the materials electronic and phonon properties.
Place, publisher, year, edition, pages
ELSEVIER , 2022. Vol. 202, article id 111004
Keywords [en]
Tantalum carbides; First-principles calculations; Isotropic Eliashberg theory; Thermodynamic stability; Superconductivity
National Category
Other Physics Topics
Identifiers
URN: urn:nbn:se:liu:diva-181637DOI: 10.1016/j.commatsci.2021.111004ISI: 000722032000003OAI: oai:DiVA.org:liu-181637DiVA, id: diva2:1617343
Note
Funding Agencies|Second Century Fund (C2F), Chulalongkorn University; National Research Council of Thailand (NRCT)National Research Council of Thailand (NRCT) [NRCT5-RSA63001-04]; Chulalongkorn UniversityChulalongkorn University; Office of the Permanent Secretary, Ministry of Higher Education, Science, Research and Innovation: Research Grant for New Scholar (RGNS) [RGNS 63-013]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Swedish Foundation for Strategic Research through the Future Research Leaders 6 program [FFL 15-0290]; Swedish Research Council (VR)Swedish Research Council [2019-05403]; Knut and Alice Wallenberg Foundation, Sweden (Wallenberg Scholar Grant) [KAW-2018.0194]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2018-05973]
2021-12-062021-12-062022-02-18