First‐Principles Study of Superconducting ScRhP and ScIrP pnictides

• Published in: physica status solidi (b) 2017-11, Vol.254 (11), p.n/a
• Main Authors: Nasir, M. T., Hadi, M. A., Rayhan, M. A., Ali, M. A., Hossain, M. M., Roknuzzaman, M., Naqib, S. H., Islam, A. K. M. A., Uddin, M. M., Ostrikov, K.
• Format: Article
• Language: English
• Subjects: elastic tensors; electronic structure; superconducting pnictides; superconductivity
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201700336

For the first time, we have reported in this study an ab initio investigation on elastic properties, Debye temperature, Mulliken population, Vickers hardness, and charge density of the two recently synthesized superconducting ScRhP and ScIrP pnictides. The optimized cell parameters show fair agreement with the experimental results. The mechanical stability of both ternary phosphides is confirmed via the calculated elastic constants. Both compounds are ductile in nature and damage tolerant. ScIrP is expected to be elastically more anisotropic than ScRhP. The estimated value of Debye temperature predicts that ScRhP is thermally more conductive than ScIrP and the phonon frequency in ScRhP is higher than that in ScIrP. Both pnictides are soft and easily machinable due to their low Vickers hardness. Moreover, the hardness of ScRhP is lower due to the presence of antibonding Rh–Rh in ScRhP. The metallic conductivity of ScRhP reduces significantly when Rh is replaced with Ir. The main contribution to the total density of states (TDOS) at Fermi‐level (EF) comes from d‐electrons of Sc and Rh/Ir in both pnictides. These two ternary compounds are characterized mainly by metallic and covalent bonding with little ionic contribution. The calculated superconducting transition temperatures fairly coincide with the reported measured values. ScRhP and ScIrP are two pnictide superconductors that crystallize in the ordered hexagonal Fe2P‐type structure. Both pnictides show superconductivity with Tc of ∼2 and 3.4 K, respectively. They are elastically anisotropic and ductile in nature. ScRhP is expected to be thermally more conductive and more machinable than ScIrP. The covalent bonding dominates in ScIrP compared to ScRhP.