Insights into the physical properties of a new 211 MAX phase Nb2CuC

M. A. Hadi, Nikolaos Kelaidis, S. H. Naqib, A.K.M.A. Islam, Alexander Chroneos, R. V. Vovk

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

A systematic density functional theory study with two functionals –generalized gradient approximation (GGA) and local density approximation (LDA)–is carried out to explore the structural, electronic, elastic, thermal, vibrational and optical properties of a new 211 MAX phase Nb2CuC. To facilitate comparison we also study Nb2AlC, the precursor of Nb2CuC. The calculated band structures reveal the metallic conductivity of both compounds. The replacement of Al with Cu modifies the band profiles of Nb2CuC and consequently leads to its improved physical properties. Considering the position of the Fermi level on the total density of states (DOS), the new compound Nb2CuC is structurally less stable than Nb2AlC. The total DOS at the Fermi level obtained with GGA is slightly larger than those obtained with LDA. The Nb–C and Nb–A (A = Cu/Al) are covalent bonds, and Nb–Nb bonds lead to antibonding states in both MAX phases. The charge transfer among constituent atoms indicates some ionic character in the chemical bonds of Nb2CuC and Nb2AlC. Both MAX phases are mechanically and dynamically stable. The Nb2CuC is ductile and consequently damage tolerant, whereas Nb2AlC is brittle. However, Nb2CuC is relatively soft and machinable. In most cases Nb2CuC is more elastically anisotropic than Nb2AlC, and Nb2CuC is expected to be a promising thermal barrier coating material. We propose that Nb2CuC is a better coating material for preventing solar heating than Nb2AlC, and Nb2CuC is expected to be superconductive because its Fermi surface has a nesting nature.
Original languageEnglish
Article number109759
Number of pages16
JournalJournal of Physics and Chemistry of Solids
Volume149
Early online date20 Oct 2020
DOIs
Publication statusPublished - Feb 2021

Bibliographical note

NOTICE: this is the author’s version of a work that was accepted for publication in Physics and Chemistry of Solids. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Physics and Chemistry of Solids, 149, (2021) DOI: 10.1016/j.jpcs.2020.109759

© 2021, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

Keywords

  • Electronic structure
  • Mechanical properties
  • New MAX phase
  • Optical functions

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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