Crystal structures of <i>X</i>‐phase in the Sb–Te binary alloy system

Kifune, Kouichi; Fujita, Takahisa; Tachizawa, T.; Kubota, Yoshiki; Yamada, Noboru; Matsunaga, Toshiyuki

doi:10.1002/crat.201300252

Cited by 20 publications

(12 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…15 Doping can change q, substantially affecting the transport properties of TE materials, especially κ; for example, doping Sr and Ca in the BiS block in BiS(TiS 2 ) 2 triggers a transition from an incommensurate (rational q) to commensurate structure (irrational q), increasing κ. 17 While the structural periodicity of homologous compounds can be sensitive to heat treatment and/or composition, 7,18 we found in the present paper that substituting In for Sb in GeSb 6 Te 10 barely affected the periodicity of its modulated structure. Table SI of the supplementary material 15 lists the lattice parameters a 3-layer , c 3-layer , and lattice volume V 3-layer based on a three-layer unit cell.…”

contrasting

confidence: 46%

Enhanced thermoelectric performance of In-substituted GeSb6Te10 with homologous structure

et al. 2014

View full text Add to dashboard Cite

We studied the crystal structure and thermoelectric properties of polycrystalline GeInxSb6−xTe10 (x = 0, 0.18, 0.3, and 0.6). Rietveld and Le Bail analyses showed that all compositions crystallized in trigonal structures with a 51-layer period. Substituting In decreased both the lattice and electronic thermal conductivity, as well as markedly increased the Seebeck coefficient. We ascribed this increase to increases in the effective mass of the carriers, likely caused by the formation of additional energy states near the Fermi level. In GeIn0.6Sb5.4Te10, we found a maximum ZT of 0.75 at 710 K, 1.9 times higher than that of GeSb6Te10.

show abstract

contrasting

confidence: 46%

Enhanced thermoelectric performance of In-substituted GeSb6Te10 with homologous structure

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Since it has limited solubility to Sb with relatively moderate slope of Sb-solvus, it is likely to decompose to δ+Sb 2 Te 3 phase mixture [28,29,[100][101][102][103], whereas Sb 2 Te 3 is equilibrium phase and may appear as diferent homologous forms [72,73,[104][105][106][107]. Precipitation of antimony-telluride second phase in δ-matrix is expected to afect TE performance due to contributions from both matrix and precipitate phases or variation of the average matrix composition.…”

Section: Formation Of Sb 2 Te 3 and Sb 8 Te 3 (R-3m) Phasesmentioning

confidence: 99%

Silver-Antimony-Telluride: From First-Principles Calculations to Thermoelectric Applications

Amouyal¹

2016

Thermoelectrics for Power Generation - A Look at Trends in the Technology

View full text Add to dashboard Cite

Silver-antimony-telluride (AgSbTe 2 ) based compounds have emerged as a promising class of materials for thermoelectric (TE) power generation at the mid-temperature range. This Chapter demonstrates utilization of irst-principles calculations for predicting TE properties of AgSbTe 2 -based compounds and experimental validations. Predictive calculations of the efects of La-doping on vibrational and electronic properties of AgSbTe 2 compounds are performed applying the density functional theory (DFT), and temperature-dependent TE transport coeicients are evaluated applying the Bolzmann transport theory (BTE). Experimentally, model ternary (AgSbTe 2 ) and quaternary (3 at. % La-AgSbTe 2 ) compounds were synthesized, for which TE transport coeicients were measured, indicating that thermal conductivity decreases due to La-alloying. The later also reduces electrical conductivity and increases Seebeck coeicients. All trends correspond with those predicted from irst-principles. Thermal stability issues are essential for TE device operation at service conditions, e.g. changes of matrix composition and second-phase precipitation, and are also addressed in this study on both computational and experimental aspects. It is shown that La-alloying afects TE igure-of-merit positively, e.g., improving from 0.35 up to 0.50 at 260 °C. We highlight the universal aspects of this approach that can be applied for other TE compounds. This enables us screening their performance prior to synthesis in laboratory.Keywords: silver-antimony-telluride, irst-principles calculations, thermoelectric transport properties, Bolzmann transport theory, latice dynamics, thermal stability IntroductionIt is of utmost technological importance to develop predictive tools that will provide us with information about design of materials' functional properties. In this context, density functional theory (DFT) irst-principle calculations ofer us such possibilities [1][2][3][4] Despite of relatively high ZT values of AgSbTe 2 phase, it is still challenging to increase them to the range of 2-3. Reaching at this limit will enable us employing this material for energy conversion at power levels >500 W [34]. Reduction in latice thermal conductivity is a conventional way to enhance TE performance and is achieved by either doping with solute elements [35] or formation of second phases to stimulate phonon scatering [36][37][38]. These latice defects afect, of course, electronic properties, mainly electrical conductivity and Seebeck coeicient. Atempts to improve TE properties of AgSbTe 2 -based alloys by doping with diferent elements [19,25,[39][40][41][42][43][44][45][46][47] Notwithstanding the aforementioned successful experimental and computational atempts, a set of experimental routines, that is initiated and directed by predictions from irst principles for complete TE performance or any other computational procedure, is missing. Thermoelectrics for Power Generation -A Look at Trends in the Technology 148A signiicant step in this direction is introduced by o...

show abstract

“…If the sample is heated, the crystallization process advances, and the structure continuously changes, eventually stabilizing into a homologous structure corresponding to the specimen composition. The homologous structure is an intergrowth structure constituted by two basic structures, the Sb phase and the Sb 2 Te 3 phase with the atomic level, and its composition can be described by the chemical formula (Sb 2 ) n (Sb 2 Te 3 ) m (where n and m are integers) [6]. In the Bi-Te binary system, which is a same V-VI system, the intermetallic compound Bi 2 Te 3 exists at 60 at.% Te.…”

Section: Introductionmentioning

confidence: 99%