Stability, electronic and phononic properties ofβand 1T structures of SiTe_x(x= 1, 2) and their vertical heterostructures

Abstract

By performing first-principles calculations, we predict a novel, stable single layer phase of silicon ditelluride, 1T-[Formula: see text], and its possible vertical heterostructures with single layer β-SiTe. Structural optimization and phonon calculations reveal that 1T-[Formula: see text] structure has a dynamically stable ground state. Further analysis of the vibrational spectrum at the [Formula: see text] point shows that single layer 1T-[Formula: see text] has characteristic phonon modes at 80, 149, 191 and 294 [Formula: see text]. Electronic-band structure demonstrates that 1T-[Formula: see text] phase exhibits a nonmagnetic metallic ground state with a negligible intrinsic spin-orbit splitting. Moreover, it is shown that similar structural parameters of 1T-[Formula: see text] and existing β-SiTe phases allows construction of 1T-β heterostructures with a negligible lattice mismatch. In this regard, it is found that two energetically favorable stacking orders, namely AA and [Formula: see text]B, have distinctive shear and layer breathing phonon modes. It is important to note that the combination of semiconducting β-SiTe and metallic 1T-[Formula: see text] building blocks forms ultra-thin Schottky barriers that can be used in nanoscale optoelectronic device technologies.

Pressure-Induced Insulator–Metal Transition in Silicon Telluride from First-Principles Calculations

“…First-principles calculations and experiments show that it possesses anisotropic optical properties. , Experiments by Wang et al show that its optoelectronic properties can be modified through doping and intercalation of Ge and Cu without altering the fundamental host lattice . Other members of the Si–Te family, such as SiTe and SiTe 2 , are also confirmed and have shown interesting properties. − A recent theoretical investigation discovered a novel structure of SiTe 2 that is more stable than the CdI 2 type that is common in MX 2 compounds, which again manifests the uniqueness of this material system.…”

Predicting a Novel Phase of 2D SiTe2

“…The silicon telluride (Si 2 Te 3 ) , is the most studied Si x –Te y compound. − It is the only known IV 2 –VI 3 material with a layered structure , and features a unique structural variability because of the orientation of silicon dimers . The other Si x –Te y compound is silicon ditelluride (SiTe 2 ), − whose electrical, thermal, and magnetic properties have recently drawn a number of investigations. − The crystal structure of SiTe 2 is identified to be the CdI 2 -type , as other 2D IV–VI 2 materials, although it was suggested that it might also exist in the Si 2 Te 3 structure with Si deficiency …”

Ultralow lattice thermal conductivity and electronic properties of monolayer 1T phase semimetal SiTe2 and SnTe2

“…A silicon based layered nanostructures of silicon telluride Si2Te3 have been synthesized successfully [15]. After that, bulk material SiTe2 has also been found via quantum-chemical techniques [16] and the electronic properties of monolayer SiTe2 have been studied [17]. In this paper, we would like explore to some new 1T phase telluride materials with many excellent mechanical and thermoelectric properties.…”