Direct observation of melted Mott state evidenced from Raman scattering in 1T-TaS2 single crystal

• 来源期刊: 中国物理B（英文版）
• 关键词: two-dimensional materials charge density wave Mott state Raman scattering
• 年，卷（期）: 2018,（1）
• 页码范围: 192-196
• 页数: 5页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/1/017104

摘要

The evolution of electron correlation and charge density wave (CDW) in 1T-TaS2 single crystal has been investi-gated by temperature-dependent Raman scattering, which undergoes two obvious peaks of A1g modes about 70.8 cm?1 and 78.7 cm?1 at 80 K, respectively. The former peak at 70.8 cm?1 is accordant with the lower Hubbard band, resulting in the electron-correlation-driven Mott transition. Strikingly, the latter peak at 78.7 cm?1 shifts toward low energy with increasing the temperature, demonstrating the occurrence of nearly commensurate CDW phase (melted Mott phase). In this case, phonon transmission could be strongly coupled to commensurate CDW lattice via Coulomb interaction, which likely induces appearance of hexagonal domains suspended in an interdomain phase, composing the melted Mott phase characterized by a shallow electron pocket. Combining electronic structure, atomic structure, transport properties with Ra-man scattering, these findings provide a novel dimension in understanding the relationship between electronic correlation, charge order, and phonon dynamics.