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Quantum Oscillations and Superconductivity in YPtBi Under Pressure

Jared Z. Dans, Prathum Saraf, Lillian Jirousek, Carsyn L. Mueller, Chandra Shekhar, Claudia Felser, Johnpierre Paglione

Abstract

The topological semimetal YPtBi has attracted considerable attention, owing to its novel superconducting and normal state properties. A strong band inversion from spin-orbit coupling allows the existence of $j=3/2$ quasiparticles near the Fermi level, which form Cooper pairs with angular momentum potentially higher than single or triplet states. In this report, we present high-pressure magnetotransport and Shubnikov-de Haas effect measurements on high-quality YPtBi up to $P = 2.08$ GPa. As a function of pressure, we observe a trend toward more insulating resistivity at low temperatures concomitant with a suppression of quantum oscillation amplitude. Together with a decrease of the upper critical field and significant increase in the Dingle temperature, the pressure-induced changes point to a weakening of the band inversion and potential tuning of the topological nature of YPtBi, suggesting pressure as a useful tool for understanding the nature of topology in other related half-Heusler compounds.

Quantum Oscillations and Superconductivity in YPtBi Under Pressure

Abstract

The topological semimetal YPtBi has attracted considerable attention, owing to its novel superconducting and normal state properties. A strong band inversion from spin-orbit coupling allows the existence of quasiparticles near the Fermi level, which form Cooper pairs with angular momentum potentially higher than single or triplet states. In this report, we present high-pressure magnetotransport and Shubnikov-de Haas effect measurements on high-quality YPtBi up to GPa. As a function of pressure, we observe a trend toward more insulating resistivity at low temperatures concomitant with a suppression of quantum oscillation amplitude. Together with a decrease of the upper critical field and significant increase in the Dingle temperature, the pressure-induced changes point to a weakening of the band inversion and potential tuning of the topological nature of YPtBi, suggesting pressure as a useful tool for understanding the nature of topology in other related half-Heusler compounds.
Paper Structure (5 sections, 4 equations, 4 figures)

This paper contains 5 sections, 4 equations, 4 figures.

Table of Contents

  1. Introduction
  2. Experimental Methods
  3. Results and Discussion
  4. Conclusion
  5. Acknowledgments

Figures (4)

  • Figure 1: Evolution of transport behavior in YPtBi under pressure. (a) Resistivity as a function of temperature at selected pressures. Empirical power law fits to Eq. \ref{['eq:PowerLaw']} were performed below 100 K (inset) to characterize the evolution of the resistivity. (b) Low temperature magnetoresistance under pressure. Large Shubnikov-de Haas oscillations can be seen at all pressures.
  • Figure 2: Pressure-dependent Shubnikov-de Haas quantum oscillations. (a) Oscillations $\Delta R$ extracted from the magnetoresistance. Under pressure, the oscillations show similar amplitudes at high field, but show stronger damping. (b) The pressure dependence of the oscillation frequency (inset) was determined via FFT (main). The oscillation frequency is largely unchanged by pressure.
  • Figure 3: Pressure-dependent effective mass and scattering time in YPtBi. (a) Temperature-dependent QO amplitudes at 0 and 2.08 GPa. Symbols represent experimental data while solid lines represent the best fit to the $A_T$ term of the LK formula (Eq. \ref{['eq:AT']}). (b) Dingle plot of the QOs: $\ln(\Delta R/A_T\sqrt{\mu_0 H})$ as a function of $1/\mu_0H$ at $T = 2$ K. The symbols represent data while the solid lines represent linear fits.
  • Figure 4: Superconductivity in YPtBi under pressure. (a) The superconducting transition at 0 (top) and 2.08 GPa (bottom). Magnetic field is applied in-plane with and perpendicular to the current. (b) Temperature variation of $H_{c2}$ under pressure. The application of pressure has no appreciable effect on the zero field $T_c$ but broadens the transition and suppresses $H_{c2}.$