arXiv subjects

Ryoma Tsunoda

Publications and source records attributed to Ryoma Tsunoda.

3 recordsLinked to original sources

arXiv2025

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

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.

cond-mat.str-el↗

arXiv2022

High-Field Ultrasonic Study of CeIrIn$_5$

We performed ultrasonic and temperature measurements under pulsed magnetic fields on CeIrIn$_5$ to investigate whether or not the origin of metamagnetic transition and field-induced Lifshitz transition was described by the anisotropic electronic ordering with crystal symmetry breaking. We observed elastic anomalies with the negative magnetocaloric effects around the field-induced Lifshitz transition and the metamagnetic transition. On the other hand, the elastic anomalies appeared both in the transverse elastic constants $(C_{11} - C_{12})/2$ and $C_{66}$ in CeIrIn$_5$ while $(C_{11} - C_{12})/2$ showed significant elastic anomaly at the crystal symmetry breaking fields in CeRhIn$_5$. These results indicate that the anisotropic electronic ordering with crystal symmetry breaking is absent in high-magnetic fields in CeIrIn$_{5}$.

cond-mat.str-el↗

arXiv2016

First-Order Structural Change Accompanied by Yb Valence Transition in YbInCu4

A diffraction experiment using a high energy x-ray was carried out on YbInCu4. Below the Yb valence transition temperature, the splitting of Bragg peaks was detected in higher-order reflections. No superlattice reflections accompanying the valence ordering were found below the transition temperature. These experimental findings indicate that a structural change from a cubic structure to a tetragonal structure without valence ordering occurs at the transition temperature. Such a structural change free from any valence ordering is difficult to understand only in terms of Yb valence degrees of freedom. This means that the structural change may be related to electronic symmetries such as quadrupolar degrees of freedom as well as the change in Yb valence.

cond-mat.str-el↗