Phonon dispersion and electronic structure in quasi-one-dimensional layered Ta2NiSe7 single crystal

The formation mechanism of charge density wave (CDW) order in layered systems was believed to arise from momentum-dependent electron-phonon coupling and electronic structure instability induced by Fermi surface nesting. Herein, we systematically investigated the angular dependence of the Raman peak intensity in a ternary layered Ta2NiSe7 single crystal through polarized Raman spectroscopy. Combining group theory analysis, the vibrational modes of the Raman peaks were clearly indentified, and the Raman shift was confirmed by our first-principle calculated phonon spectrum. In addition, the electronic band structure near the Fermi level simulated via ab initio density functional theory coincided with angle resolved photoelectron spectroscopy measurements (ARPES). Our study provided a useful foundation for further understanding the CDW transition in layered Ta2NiSe7.

Automated summary

In this study, we investigated the angular dependence of Raman peak intensity in a ternary layered Ta2NiSe7 single crystal, identifying vibrational modes and confirming the Raman shift through first-principle calculations. The electronic band structure near the Fermi level simulated via density functional theory matched ARPES measurements, laying a useful foundation for understanding the CDW transition in Ta2NiSe7.