Theoretical Analysis of Electronic, Vibrational and Thermal Properties for Single-Layer and Chain Quasi 1D Materials (TaSe₃ and ZrTe₃)

Quasi 1D materials have recently received much interest due to their unique properties such as charge density waves, superconductivity, non-trivial topology, high current capacity, anisotropic behavior etc. The unique properties of these materials are attributed to the presence of 1D chains weakly bonded together while the plane of chains is separated by weaker van der Waals bonds. Much work has been done to understand the bulk form of these materials, but the study of extreme cross-sectional properties (layer and chain) is just beginning. In this work, we study the electronic, vibrational, and thermal properties of transition-metal trichalcogenide (TMT) quasi 1D material as the thicknesses of these materials are decreased (bulk to monolayer to single chain). We focus on TaSe₃ and ZrTe₃ due to their potential as interconnect and understanding their properties at extreme scales will help us to realize their performance under ultra-scaled cross-sections. Both TaSe₃ and ZrTe₃ are TMT materials with monoclinic configurations. The transition metal (M =Ta, Zr) of these materials sits at the center of a prism surrounded by chalcogen (X=Se, Te) atoms. Thus, a strong M-X covalently bonded chain is created by these prisms which are connected side-by-side via longer, weaker M-X bonds, and planarly stacked with even weaker van der Waals type bonds that makes them quasi 1D in nature. Using Density Functional Theory (DFT) calculations, we analyzed the vibrational properties of these materials. Our phonon calculation shows that, the monolayer structures are dynamically stable. Also, the spin orbit coupling (SOC) in monolayer TaSe₃results in a small bandgap due to the anti-crossing of bands near the Fermi level, which is not present in its bulk counterpart.<br/>Funding Acknowledgement: This work was funded in part by ONR award number N00014-21-1-2947 under the Vannevar Bush Faculty Fellowship awarded to A. A. Balandin. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant No. ACI-1548562 and allocation ID TGDMR130081.