Raman and Infrared Spectra of Tellurium Sub‐Bromide (Te₂Br)

Abstract

Raman and I R spectroscopic techniques are used to study the long-wavelength optical phonons of tellurium sub-bromide (orthorhombic structure). By use of an appropriate range of temperatures and excitation wavelengths the frequencies for nearly all of the A, and B, q x 0 optical phonons are determined. Oscillator strengths and LO-frequencies for these phonons are obtained from the fitting of IR reflection spectra with a multiple oscillator model. The temperature dependence of the frequency and damping constant for some of these phonons is discussed. A remarkable feature of this material is the existence of low frequency (:= 20 cm-l) phonons with extremely large polarizabilities (Ax up to 150).Raman-und IR-Spektroskopie werden benutzt, um die langwelligen optischen Phononen von Tellursubbromid (rhombische Struktur) zu untersuchen. Durch geeignete Wahl des Temperaturbereichs und der Anregungswellenlangen werden nahezu alle optischen 4und B,-Phononen mit q x 0 bestimmt. Die Oszillatorstarken und LO-Frequenzen dieser Phononen werden aus der Anpassung der IR-Reflexionsspektren an ein Mehrfachoszillatormodell erhalten. Die Temperaturabhiingigkeit der Frequenz und die Dampfungskonstante fur einige dieser Phononen wird diskutiert. Eine bemerkenswerte Eigenschaft dieses Materials ist die Existenz von Phononen niedriger Frequenz (x 20 cm-l) mit extrem groDer Polarisierbarkeit (Ax bis zu 150).

Telluride Te2I: Electronic properties of one-dimensional atomic chains structure

“…Due to all tellurium sub-halides crystallize are coordinated by halogen elements according to the arrangement of the Te element's threefold screw axis, they exhibit similar structural properties to Te crystals. [17] Interestingly, there are also interchain vdW interaction forces in the bulk Te 2 I system. [18] Since the atomic Te chain was successfully separated from the bulk Te by mechanical exfoliation, it should be feasible to prepare a 1D Te 2 I atomic chains from the bulk Te 2 I system in the experiment.…”