Thermoelectric Properties of Stoichiometric Compounds in the (SnTe)_x(Bi₂Te₃)_y System

Abstract

Various compounds in the (SnTe)x(Bi2Te3)y series are explored by a number of techniques including diffractometry and physical property measurements. Through variation in the x and y integers, one is able to obtain a series of ternary compounds: SnBi2Te4, SnBi4Te7, SnBi6Te10, and Sn2Bi2Te5 each show complex layering motifs similar to that of Bi2Te3. These compounds' increased complexity makes them of interest with respect to thermoelectric studies. The ZT values for cold‐pressed annealed pellets are at room temperature 0.33 for SnBi2Te4, 0.27 for SnBi4Te7, and 0.15 for SnBi6Te10.

Sublattice effect on topological surface states in complex(SnTe)n>1(Bi2Te3)m

“…2(a), a direct energy gap of 0.32 eV exists at the point in the calculation without SOI, which transforms into an indirect gap of 0.11 eV after switching on the SOI [ Fig. 2(b)], which is in a good agreement with the experimental value of 0.09 eV [18]. We also examined the effect of nonlocal van der Waals (vdW) interaction on structure optimization and bulk electronic structure of Sn 2 Bi 2 Te 5 , taking it into account by the Grimme method as implemented in the VASP code.…”

“…Thus this compound differs from the Bi 2 Te 3 /SnTe heterostructure having ionic-covalent bonded Bi 2 Te 3 and SnTe atomic layers. Another experimentally confirmed structure (SnTe) n (Bi 2 Te 3 ) m , which is also built from ionic-covalent bonded Bi 2 Te 3 and SnTe atomic layers, is Sn 3 Bi 2 Te 6 (n = 3,m = 1) [18]. In this case additional SnTe layers are incorporated into the building block [ Fig.…”

“…This compound was predicted to be three-dimensional (3D) Z 2 TI with single Dirac cone in the bulk energy gap [10]. The Sn 2 Bi 2 Te 5 compound (n = 2,m = 1) is formed by nonuple layer (NL) building blocks [18]. The NL block [ Fig.…”

“…Different systems containing layers of band-inverted Bi 2 Te 3 and SnTe materials are (SnTe) n (Bi 2 Te 3 ) m compounds [18]. In this series the (n = 1,m > 1) compounds-SnBi 4 Te 7 , SnBi 6 Te 10 , and SnBi 8 Te 13 -are structurally identical to earlier studied lead-based TIs [10], containing alternating QL and SL structural units, while the (n 1,m = 1) compounds are formed by unique, nonalternating building blocks.…”

XV Международная конференция "Термоэлектрики и их применения --- 2016", Санкт-Петербург, 15-16 ноября 2016 г. Анализ кристаллической структуры сплавов семейства [(Ge,Sn,Pb)(Te,Se)]-=SUB=-m-=/SUB=-[(Bi,Sb)-=SUB=-2-=/SUB=-(Te,Se)-=SUB=-3-=/SUB=-]-=SUB=-n-=/SUB=- (m,n=0,1,2,...) в рамках теории плотнейших шаровых упаковок

“….) находят широкое применение в электронной техни-ке [1][2][3][4][5][6]. Семейства БС и ТС имеют сложную слоистую кристаллическую структуру с собственными периодами наноидентичности ξ 1,2 , изменяющимися в зависимости от соотношения m/n.…”