Year: 2012
Type: article
Abstract: Using an effective one-dimensional cluster expansion in combination with first-principles electronic structure calculations we have studied the energetics and electronic properties of Sb-Te layered systems. For a Te concentration between 0 and 60 at. $%$ an almost continuous series of metastable structures is obtained consisting of consecutive Sb bilayers next to consecutive Sb${}_{2}$Te${}_{3}$ units, with the general formula (Sb${}_{2}$)${}_{n}$(Sb${}_{2}$Te${}_{3}$)${}_{m}$ ($n,m=1,2,...$). Between 60 and 100 at. $%$ no stable structures are found. We account explicitly for the weak van der Waals bonding between Sb bilayers and Sb${}_{2}$Te${}_{3}$ units by using a recently developed functional, which strongly improves the interlayer bonding distances. At $T=0$ K, no evidence is found for the existence of two separate single-phase regions $\ensuremath{\delta}$ and $\ensuremath{\gamma}$ and a two-phase region $\ensuremath{\delta}+\ensuremath{\gamma}$. Metastable compounds with a Te concentration between 0 and 40 at. $%$ are semimetallic, whereas compounds with a Te concentration between 50 and 60 at. $%$ are semiconducting. Compounds with an odd number of Sb layers are metallic and have a much higher formation energy than those with an even number of consecutive Sb layers, thereby favoring the formation of Sb bilayers.
Source: Physical Review B
Institutions: University of Antwerp, Delft University of Technology
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2058829583