Unusual lattice vibration characteristics in whiskers of the pseudo-one-dimensional titanium trisulfide TiS3

Abstract

Transition metal trichalcogenides form a class of layered materials with strong in-plane anisotropy. For example, titanium trisulfide (TiS3) whiskers are made out of weakly interacting TiS3 layers, where each layer is made of weakly interacting quasi-one-dimensional chains extending along the b axis. Here we establish the unusual vibrational properties of TiS3 both experimentally and theoretically. Unlike other two-dimensional systems, the Raman active peaks of TiS3 have only out-of-plane vibrational modes, and interestingly some of these vibrations involve unique rigid-chain vibrations and S–S molecular oscillations. High-pressure Raman studies further reveal that the AgS–S S-S molecular mode has an unconventional negative pressure dependence, whereas other peaks stiffen as anticipated. Various vibrational modes are doubly degenerate at ambient pressure, but the degeneracy is lifted at high pressures. These results establish the unusual vibrational properties of TiS3 with strong in-plane anisotropy, and may have relevance to understanding of vibrational properties in other anisotropic two-dimensional material systems.

Synthesis of Highly Anisotropic Semiconducting GaTe Nanomaterials and Emerging Properties Enabled by Epitaxy

“…It is worth noting that the growth of GaTe is quite different in that instead of isotropic growth (i.e., material grows in all directions in the plane), monoclinic GaTe growth occurs preferably along the [010] chain direction. This chain‐like growth is directly related to the highly anisotropic crystal structure of monoclinic GaTe and will be discussed later in this Communication. Here, we also note that similar relations also exist for GaTe grown onto Si wafers but are not shown here for brevity.…”

“…Pseudo‐1D materials are a new class of materials where atoms are arranged in chain‐like structures in 2D. Examples of these materials include recently discovered black phosphorus, ReS 2 , and ReSe 2 from transition metal dichalcogenides (TMDCs), TiS 3 and ZrS 3 from transition metal trichalcogenides, and most recently gallium telluride (GaTe) . The presence of structural anisotropy impacts their physical properties and leads to direction‐dependent light–matter interactions, dichroic optical responses, high mobility channels, and anisotropic thermal conduction, which are especially attractive for optoelectronic and photonic applications …”

“…The anisotropic behavior of the monoclinic GaTe flakes is also demonstrated by ARMR spectroscopy, which has been widely used in other pseudo 1D materials such as ReS 2 and TiS 3 . The measurement is carried out in the same setup as the ARMP experiment.…”

Phase Transition across Anisotropic NbS3 and Direct Gap Semiconductor TiS3 at Nominal Titanium Alloying Limit

“…TiS 3 displays four prominent Raman modes at 176 cm −1 (A g rigid mode), 298 cm −1 (A g internal mode), 370 cm −1 (A g internal mode), and 556 cm −1 (A g s‐s mode) consistent with earlier findings. [ 37 ] Considering rich Raman spectrum (with many low intensity Raman peaks), we focus on the most prominent four modes from NbS 3 that are also found to be related and active in TiS 3 and their alloys. Specifically, the mode I at 159 cm −1 represents the Nb – Nb stretching mode.…”

Ab initio and semiempirical modeling of excitons and trions in monolayer TiS3

“…Among the recently synthesized groups of layered materials are the transition metal trichalcogenides (TMTCs) which have a chemical formula MX 3 , where M stands for a transition metal from group IV, V, or VI in the periodic table (e.g., Ti, Zr, or Nb) and X is a chalcogen atom (e.g., S, Se, or Te). TMTCs are a much less explored class of materials when compared with the extensively studied transition metal dichalcogenides (TMDCs), which are considered promising candidates for a next generation of flexible nanoelectronic devices due to their wide range of different properties [3][4][5][6][7][8][9].…”