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arXiv · 1801.01217

Dimensionality-driven orthorhombic MoTe2 at room temperature

Rui He·Shazhou Zhong·Hyun Ho Kim·Gaihua Ye·Zhipeng Ye·Logan Winford·Daniel McHaffie·Ivana Rilak·Fangchu Chen·Xuan Luo·Yuping Sun·Adam W. Tsen
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Abstract

We use a combination of Raman spectroscopy and transport measurements to study thin flakes of the type-II Weyl semimetal candidate MoTe2 protected from oxidation. In contrast to bulk crystals, which undergo a phase transition from monoclinic to the inversion symmetry breaking, orthorhombic phase below ~250 K, we find that in moderately thin samples below ~12 nm, a single orthorhombic phase exists up to and beyond room temperature. This could be due to the effect of c-axis confinement, which lowers the energy of an out-of-plane hole band and stabilizes the orthorhombic structure. Our results suggest that Weyl nodes, predicated upon inversion symmetry breaking, may be observed in thin MoTe2 at room temperature.

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Rui He, Shazhou Zhong, Hyun Ho Kim, Gaihua Ye, Zhipeng Ye, Logan Winford, Daniel McHaffie, Ivana Rilak, Fangchu Chen, Xuan Luo, Yuping Sun, Adam W. Tsen. 2018-01-04. Dimensionality-driven orthorhombic MoTe2 at room temperature. https://doi.org/10.1103/physrevb.97.041410

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