SdH oscillations and pressure effect of the Weyl semimetal NbAs

ORAL

Abstract

Via angular Shubnikov-de Hass (SdH) quantum oscillations measurements, we determine the Fermi surface topology of NbAs. The SdH oscillations consist of two frequencies, corresponding to two Fermi surface extrema: 20.8 T ($\alpha $-pocket) and 15.6 T ($\beta $-pocket). The analysis shows that the $\beta $-pocket has a Berry phase of $\pi $ and a small effective mass 0.033 m$_{\mathrm{0}}$, indicative of a nontrivial topology; whereas the $\alpha $-pocket has a trivial Berry phase of 0 and a heavier effective mass 0.066 m$_{\mathrm{0}}$. Subtle changes can be seen in the $\rho _{\mathrm{xx}}$(T) profiles with pressure up to 2.31 GPa. The Fermi surfaces undergo an anisotropic evolution under pressure, while the topological features of the two pockets remain unchanged. Specific heat measurements reveal a small Sommerfeld coefficient $\gamma _{\mathrm{0}}=$0.09(1) mJ/(mol\textbullet K$^{\mathrm{2}})$ and a large Debye temperature, $\Theta_{\mathrm{D}}=$450(9) K, confirming a ``hard'' crystalline lattice that is stable under pressure. We also studied the Kadowaki-Woods ratio of this low-carrier-density massless system, R$_{\mathrm{KW}}=$3.2\texttimes 10$^{\mathrm{4}}$\textmu $\Omega $ cm mol$^{\mathrm{2}}$K$^{\mathrm{2}}$J$^{\mathrm{-2}}$. After accounting for the small carrier density in NbAs, this R$_{\mathrm{KW}}$ indicates a suppressed transport scattering rate relative to other metals. \textbf{References:} [1] N. J. Ghimire \textit{et al}., J. Phys.: Condens. Matter \textbf{27}, 152201 (2015) [2] Y. Luo \textit{et al.}, arXiv: 1506.01751 (2015) [3] Y. Luo \textit{et al.}, arXiv: 1510.08538 (2015)

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Authors

  • Yongkang Luo

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA

  • N. J. Ghimire

    Argonne National Laboratory, Argonne, Illinois 60439, USA

  • M. Wartenbe

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA

  • Hongchul Choi

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA

  • M. Neupane

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA

  • Ross McDonald

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA, LANL, Los Alamos National Laboratory, National High MagneticField Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA.

  • Eric Bauer

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA, Los Alamos National Laboratory

  • Jian-Xin Zhu

    Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA, Los Alamos National Laboratory, Los Alamos, NM 87545, USA, Los Alamos National Laboratory

  • Joe Thompson

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA, Los Alamos National Laboratory

  • Filip Ronning

    Los Alamos National Laboratory, Los Alamos, NM 87545, USA, Los Alamos National Laboratory, Los Alamos National Lab