Electronic structure, lattice dynamics and magnetism of new ThXAsN (X=Fe,Co,Ni) superconductors: A First Principles Study

Abstract

In this work, we present a comparative first principles study of mechanical properties, electronic structure, phonon dispersion relation, electron-phonon coupling and magnetism in three isostructural superconductors, namely, ThFeAsN, ThCoAsN and ThNiAsN. Experimentally, ThFeAsN and ThNiAsN show superconducting properties, while ThCoAsN has not been synthesized. Our calculated elastic constants show that all these systems are mechanically stable. Significant differences in the electronic structures of these three compounds in terms of density of states, band structures and Fermi surfaces, are found. Our phonon calculations reveal that all the systems including ThCoAsN, are dynamically stable. Phonon dispersion relations indicate that the optical modes of all the three systems are almost the same while there are significant variations in the low frequency manifold consisting of mixed modes. The electron-phonon coupling constants and superconducting transition temperatures calculated based on the Eliashberg formalism, predict a rather high $T_c$ of 6.4 K for ThCoAsN and also a $T_c$ of 3.4 K for ThNiAsN which agrees well with the experimental value of 4.3 K. Nevertheless, we find a $T_c$ of 0.05 K for ThFeAsN, which is much smaller than the experimental $T_c$ of $\sim$30 K. However, a simple analysis considering the amplifying effects of spin density wave order and out-of-plane soft phonon modes suggests that the $T_c$ could be increased considerably to $\sim$10 K. Finally, we also discuss the effect of anion As height on the electronic structures and study possible magnetic states in these three compounds.

accepted for publication in the Phys. Rev. B

References in corpus (21)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• LaFeAsO${}_{1-x}$F${}_x$: A low carrier density superconductor near itinerant magnetism
• Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
• LiFeAs: An Intrinsic FeAs-based Superconductor with Tc = 18K
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Competing Orders and Spin-Density-Wave Instability in La(O${}_{1-x}$F${}_x$)FeAs
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Hydrogen sulphide at high pressure: a strongly-anharmonic phonon-mediated superconductor
• Superconductivity in Co-doped LaFeAsO
• Multiband magnetism and superconductivity in Fe-based compounds
• AFe2As2 (A = Ca, Sr, Ba, Eu) and SrFe_(2-x)TM_(x)As2 (TM = Mn, Co, Ni): crystal structure, charge doping, magnetism and superconductivity
• First Order Phase Transition and Superconductivity in BaNi2As2 Single Crystals
• Valley density-wave and multiband superconductivity in Fe-pnictides
• Nickel-based layered superconductor, LaNiOAs
• Density functional study of BaNi${}_2$As${}_2$: Electronic structure, phonons and electron-phonon superconductivity
• Electron Phonon Superconductivity in LaNiOP
• Superconductivity at 52 K in hydrogen-substituted LaFeAsO1-xHx under high pressure
• First-principles study of the optical properties of MgxTi(1-x)H2
• High-$T_{\mathrm{c}}$ superconductivity in undoped ThFeAsN
• Pressure induced Lifshitz transition in ThFeAsN

Cited by in corpus (3)

• Ab initio study on magnetism suppression, anharmonicity, rattling mode and superconductivity in Sc${}_{6}M$Te${}_2$ ($M$=Fe, Co, Ni)
• Exploring multichannel superconductivity in ThFeAsN
• Pressure induced antiferromagnetic-tetragonal to nonmagnetic-collapse-tetragonal insulator-metal transition in ThMnAsN