Electron-phonon superconductivity in C-doped topological nodal-line semimetal Zr${}_5$Pt${}_3$: A muon spin rotation and relaxation ($\mu$SR) study

Abstract

In the present work we demonstrate that C-doped Zr${}_5$Pt${}_3$ is an electron-phonon superconductor (with critical temperature T${}_{\mathrm{C}}$ = 3.7\,K) with a nonsymmorphic topological Dirac nodal-line semimetal state, which we report here for the first time. The superconducting properties of Zr${}_5$Pt${}_3$C${}_{0.5}$ have been investigated by means of magnetization and muon spin rotation and relaxation ($\mu$SR) measurements. We find that at low temperatures the depolarization rate is almost constant and can be well described by a single-band $s-$wave model with a superconducting gap of $2\Delta (0)/k_{\mathrm{B}}{T}_{\mathrm{C}}$ = 3.84, close to the value of BCS theory. From transverse field $\mu$SR analysis we estimate the London penetration depth ${\lambda }_L$ = 469 nm, superconducting carrier density $n_s$ = 2$\times$10${}^{26}$ $m^{-3}$, and effective mass m${}^{\ast }$ = 1.584 $m_e$. Zero field $\mu$SR confirms the absence of any spontaneous magnetic moment in the superconducting ground state. To gain additional insights into the electronic ground state of C-doped Zr${}_5$Pt${}_3$, we have also performed first-principles calculations within the framework of density functional theory (DFT). The observed homogenous electronic character of the Fermi surface as well as the mutual decrease of $T_{\mathrm{C}}$ and density of states at the Fermi level are consistent with the experimental findings. However, the band structure reveals the presence of robust, gapless fourfold-degenarate nodal lines protected by $6_3$ screw rotations and glide mirror planes. Therefore, Zr${}_5$Pt${}_3$ represents a novel, unprecedented condensed matter system to investigate the intricate interplay between superconductivity and topology.

9 pages, 5 figures

References in corpus (17)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Topological response in Weyl semimetals and the chiral anomaly
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Topological Node-Line Semimetal in Three Dimensional Graphene Networks
• Topological nodal line semimetals
• Magnetic Penetration Depth in Unconventional Superconductors
• Broken time-reversal symmetry probed by muon spin relaxation in the caged type superconductor Lu${}_5$Rh${}_6$Sn${}_{18}$
• Topological tuning in three-dimensional Dirac semimetals
• Superconductivity in intercalated group-IV honeycomb structures
• Anisotropic superconducting gaps in YNi${}_2$B${}_2$C: A first-principles investigation
• Unconventional superconductivity in the cage type compound Sc${}_5$Rh${}_6$Sn${}_{18}$
• Multigap superconductivity in ThAsFeN investigated using muSR measurements
• Probing the superconducting ground state of ZrIrSi: A $\mu$SR study
• Muon Spin Rotation and the Vortex Lattice in Superconductors

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