Vibrational properties of layered BiTeCl single crystal

Abstract

Bismuth tellurohalides have intrigued numerous interests for their novel Rashba splitting electronic structures with potential applications in spintronics and two‐dimensional (2D) optoelectronics. In this work, we have a detailed study of bulk BiTeCl and its exfoliated flakes using ultralow wavenumber Raman spectroscopy. We observe all BiTeCl characteristic Raman modes including the lowest wavenumber rigid layer in‐plane vibrational mode E32 at 19 cm−1. From 77 to 300 K, hardening of Raman modes are observed with sharpened profiles. Temperature coefficients of Raman modes except E32 are around −0.009 to −0.027 cm−1/K, showing the sensitive response of lattice vibrations to temperature, whereas E32 has a much smaller temperature coefficient of −0.004 cm−1/K and almost constant linewidth, similar to the behavior of shear mode of 2D materials. Furthermore, by using excitation lasers of 488, 514.5, 647, and 785 nm, we find that BiTeCl Raman modes are nondispersive, 2 characteristic in‐plane E modes are more pronounced for low‐energy lasers whereas out‐of‐plane A1 modes behave inversely, which could be related to the interband transitions. Our work provides valuable lattice vibrational and thermal information of BiTeCl for its integration into the emerging 2D nano devices as a promising polar layered material.

First-principles study on structural, vibrational, elastic, piezoelectric, and electronic properties of the Janus BiXY ( X=S,Se,T

“…In another experimental study, it has been reported that the BiTeCl is a semiconductor with an electronic band gap of 0.77 eV at room temperature, which makes it a suitable material for infrared detector and sensing applications [34,35]. The vibrational properties of bulk and exfoliated flakes of BiTeCl have been examined by Raman spectroscopy, providing basic information on lattice dynamics [36]. Furthermore, theoretical calculations and experimental analysis have demonstrated pressure-induced topological phase transitions and superconductivity in BiTeX crystals [37][38][39].…”

Phase transition and trigger mechanism of initial reaction under pressure for benzofuroxan energetic materials: Raman spectroscopy and first‐principle calculations

“…The main strength of the Raman spectroscopy is able to provide a great wealth of molecular vibration information. [ 40,41 ] The experimental Raman spectra of benzofuroxan at the selected pressure in the spectral range of 400–1,700 cm −1 have been shown in Figure 2. It can be seen that there are about 15 Raman bands ( v 1 –v 15 ) that can be observed at ambient pressure.…”

Epitaxial Synthesis of Highly Oriented 2D Janus Rashba Semiconductor BiTeCl and BiTeBr Layers

“…To confirm the presence of BiTeCl sheets, we have used conventional nondestructive Raman spectroscopy. Previously, this method has been widely used to characterize bulk BiTeCl ,, as well as other Janus crystals with well-established Raman spectra. Vibrational representation of zone-center phonons of BiTeCl can be written as Γ = 2A 1 +3B 1 +2E 1 +2E 2 where all the modes should be observed except silent B 1 modes.…”