Optical study of three-dimensional Weyl semimetal Mn${}_3$Sn

Abstract

Three-dimensional (3D) Weyl semimetal Mn${}_3$Sn has attracted tremendous attention due to its great application potential. However, the complex magnetic structures at different temperature intervals make it extremely difficult to unravel the underlying electronic structures of Mn${}_3$Sn. Here, we perform temperature-dependent optical spectroscopy measurements on single crystalline Mn${}_3$Sn to investigate its charge dynamics. We find that both of the optical reflectivity $R(\omega )$ and conductivity ${\sigma }_1(\omega )$ evolve very smoothly across the magnetic phase transition at $T_M$ = 285 K, where the giant anomalous Hall effect (AHE) at room temperature drops significantly. Furthermore, two linearly increasing segments of ${\sigma }_1(\omega )$ are observed in the whole temperature range from 300 K to 10 K, indicating that the existence of Weyl fermions is very robust against the magnetic phase transition. In addition, the Weyl points closest to the Fermi level $E_F$ are identified to be located about 101 meV away from $E_F$ at 10 K, and the associated Fermi velocity is about 2.55 $\times 10^7$ cm/s. Our results reveal that the phase transition at $T_M$ only generates subtle modification to the band structure, which helps to further uncover the mechanism of the dramatic change of AHE in Mn${}_3$Sn.

References in corpus (10)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
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• Anomalous thermoelectric phenomena in lattice models of multi-Weyl semimetals
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Cited by in corpus (2)

• Hydrostatic and chemical pressure driven crossover from commensurate to the incommensurate state of the Weyl semimetal Mn${}_{3+x}$Sn${}_{1-x}$
• Localized surface plasmons in a Weyl semimetal nanosphere