arXiv subjects

Mizuki Akei

Publications and source records attributed to Mizuki Akei.

2 recordsLinked to original sources

arXiv2026

Phonon scattering mechanisms in WTe$_2$ observed by ultrafast coherent phonon spectroscopy

Revealing the mechanisms of phonon scattering is crucial for understanding material properties such as transport characteristics and optical responses. It can be discussed by measuring the temperature dependence of the phonon energy and lifetime. To gain insight into these mechanisms in Weyl semimetal T$_d$-WTe$_2$, we investigated coherent phonons using time-resolved pump-probe spectroscopy in a wide temperature range from 4.6 to 300 K. The temperature dependence of the frequency and decay rate of the two high-frequency optical modes was described by the conventional anharmonic phonon-phonon scattering model. In contrast, the low-frequency mode at 2.4 THz exhibited anomalous behavior, which can be interpreted as the contribution of phonon-electron scattering.

cond-mat.mtrl-sci↗

arXiv2025

Role of interlayer shear phonons on lattice symmetry switching in the transition metal dichalcogenide WTe$_{2}$

Coherent phonon control using ultrashort pulse trains is the key to realizing structural phase transitions in solids by non-thermal pathways. By combining double-pulse excitation and time-resolved second harmonic generation techniques under high-density electronic excitation in a 2D layered material, WTe$_{2}$, we demonstrate that the lattice symmetry switching from the Weyl semimetallic T$_{d}$ to the semimetallic 1T$^{\prime}$ phases is independent of the amplitude of the coherent interlayer shear phonons after the arrival of the second pump pulse. This finding provides new insights into the mechanisms for symmetry switching that electronic excitation-driven shear sliding plays a dominant role.

cond-mat.mtrl-sci↗