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Ultrasonic observation of small Fermi surfaces in La$T$In$_5$ ($T$ = Co, Rh, Ir)

Ryosuke Kurihara, Yusuke Hirose, Kazuki Matsui, Atsushi Miyake, Ryoma Tsunoda, Masaki Kondo, Rikio Settai, Mitsuhiro Akatsu, Yuichi Nemoto, Hiroshi Yaguchi, Masashi Tokunaga

Abstract

We performed high-field ultrasonic measurements on La$T$In$_5$ ($T$ = Co, Rh, Ir) to reveal the origin of the small Fermi surface that was recently observed in LaRhIn$_5$ with an oscillation frequency of 6.8 T. We observed quantum oscillations originating from this Fermi surface in LaRhIn$_5$. In addition, we revealed that LaCoIn$_5$ and LaIrIn$_5$ exhibit quantum osciilations with frequencies below 100 T, indicating hidden Fermi surfaces in these compounds. Furthermore, Co-substituted LaRhIn$_5$ exhibited quantum oscillations with a frequency of 10 T. Our results suggest that the small Fermi surface originates from bulk properties and that $3d$ electrons of the transition metal contribute to its formation.

Ultrasonic observation of small Fermi surfaces in La$T$In$_5$ ($T$ = Co, Rh, Ir)

Abstract

We performed high-field ultrasonic measurements on LaIn ( = Co, Rh, Ir) to reveal the origin of the small Fermi surface that was recently observed in LaRhIn with an oscillation frequency of 6.8 T. We observed quantum oscillations originating from this Fermi surface in LaRhIn. In addition, we revealed that LaCoIn and LaIrIn exhibit quantum osciilations with frequencies below 100 T, indicating hidden Fermi surfaces in these compounds. Furthermore, Co-substituted LaRhIn exhibited quantum oscillations with a frequency of 10 T. Our results suggest that the small Fermi surface originates from bulk properties and that electrons of the transition metal contribute to its formation.

Paper Structure

This paper contains 5 sections, 3 figures.

Table of Contents

  1. Introduction
  2. Experimental methods
  3. Results
  4. Discussion
  5. Conclusion

Figures (3)

  • Figure 1: (a) Magnetic field dependence of the longitudinal elastic constant $\mathit{\Delta}C_{11} = C_{11}\left( H \right) - C_{11}\left( H = 0 \right)$ at 2.5 K for $\boldsymbol{H}//[001]$. (b) Power spectra of the fast Fourier transform of $\mathit{\Delta}C_{11}$ in the range of 1 to 7 T. The inset in panel (b) shows the FFT spectra in the range of 10 to 12 T. The vertical arrows indicate oscillation frequencies of 0.6, 1.8, 3.7, 4.6, and 7.6 kT. (c) Magnetic field dependence of the transverse elastic constant $\mathit{\Delta}C_{44} = C_{44}\left( H \right) - C_{44}\left( H = 0 \right)$ at 1.4 K for $\boldsymbol{H}//[001]$. $\mathit{\Delta} C_{44}$ indicated by the black (green) open circles is measured by the pulsed magnetic fields with a maximum field of 52 T (21 T). (d) Power spectra of the fast Fourier transform of $\mathit{\Delta}C_{44}$. The inset in panel (d) shows the inverse magnetic field dependence of $\mathit{\Delta} C_{44}$ measured by the pulsed magnetic fields with a maximum field of 21 T in the range of 3 to 20 T. The vertical arrows indicate oscillation frequencies of 45.0 T (43.2 and 50.2 T) for the FFT range of 7 to 50 T(3 to 20 T).
  • Figure 2: (a) Magnetic field dependence of the phase difference $-\mathit{\Delta}\phi_\mathrm{L}$ of the in-plane longitudinal elastic constant of LaCoIn$_5$ at several temperatures for $\boldsymbol{H}//[001]$. The data sets are shifted consequently along the $-\mathit{\Delta}\phi_\mathrm{L}$ axes for clarity. (b) Magnetic field dependence of the phase difference $-\mathit{\Delta}\phi_\mathrm{L[110]}$ of the in-plane longitudinal elastic constant of LaCo$_{0.1}$Rh$_{0.9}$In$_5$ at 1.4 K for $\boldsymbol{H}//[001]$. The inset in panel (b) shows the inverse magnetic field dependence of $-\mathit{\Delta}\phi_\mathrm{L[110]}$.
  • Figure 3: Material dependence of the oscillation frequency of the small Fermi surface in La$T$In$_5$ ($T =$ Co, Rh, Ir) for $\boldsymbol{H}//[001]$. The dotted line indicates the linear fit of the oscillation frequencies of LaCo$_{1-x}$Rh$_x$In$_5$.