Evolution of the Fermi surface of 1T-VSe2 across a structural phase transition

量子物理学・ナノサイエンス第384回セミナー

概要

Two-dimensional (2D) layered transition metal dichalcogenides (TMDCs) display a variety of electronic, magnetic, and transport properties, making them widely studied materials1. Among the many TMDCs, 1T-VSe₂ gained special attention due to its three-dimensional charge density wave (3D-CDW) phase². The structural distortion sets in at a transition temperature of 110 K presenting a 4a x 4a x 3c periodic superlattice. Early photoemission experiments viewed a shift of a secondary peak and a warping effect along the kz direction as signatures of the CDW phase^3-5.

Here, we revisit the surface electronic structure of 1T-VSe₂ aiming to investigate the CDW phase in more detail. ARPES results virtually identical to the previous reports are reproduced. Additional states are also revealed that were not observed or predicted before. Furthermore, a prominent effect associated with the CDW phase is found in the shrinkage of the electron pocket centered at (M') ̅-point at 100 ± 5 K. This observation is in excellent agreement with transport measurements. The new findings can clarify many of the electronic and transport anomalies of 1T-VSe₂.

References

　　　　
• [1] Manzeli, S. et al. Nat. Rev. Mater. 2, 17033 (2017).
• [2] Tsutsumi, K. Phys. Rev. B 26, 5756–5759 (1982).
• [3] Terashima, K. et al. Phys. Rev. B 68, 155108 (2003).
• [4] Sato, T. et al. J. Phys. Soc. Jpn. 73, 3331 (2004).
• [5] Strocov, V. N. Phys. Rev. Lett. 109, 086401 (2012).
　　

• 量子物理学・ナノサイエンス第384回セミナー

• 東京工業大学理学院・物理学系 ナノサイエンスを拓く量子物理学拠点　共催