Electrical Properties of Bi<sub>2</sub>Te<sub>3</sub>

Shigetomi, S.; Mori, Shigeyasu

doi:10.1143/jpsj.11.915

Cited by 53 publications

(25 citation statements)

References 4 publications

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“…In summary, we have checked the electronic structure and TE properties of GBT compounds for [59][60][61][62][63][64], the p-type GBT with m = 8, n = 1 is predicted to have best ZT upto 1.4 near room temperature. The results show that band engineering by strain and quantumconfinement effect could enhance the TE performances.…”

Section: Discussionmentioning

confidence: 99%

OptimizedZTofBi2Te3−GeTecompoun

2016

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We predict the thermoelectric properties of layered [GeTe] m [Bi 2 Te 3 ] n (GBT) compounds (1 ≤ m ≤ 8, 1 ≤ n ≤ 3), using first-principles-Boltzmann transport calculations of the homogeneous (Bi 2 Te 3 and GeTe) data. The lattice strain and the quantum-confinement effects of compounds evolve the bandgap structures, resulting in asymmetric and large Seebeck coefficient, at high GeTe content.Using semi-empirical calculations of electron scattering rate 1/ ! , dominated by electron-acoustic phonon scattering, we reproduce reported TE properties of GBT compounds. We predict that due to small Seebeck coefficient, the GBT compounds with high n-and p-type doping (~10 20 cm -3 ), do not have high ZT near room temperature. However, we predict that the moderately-doped (~10 19 cm -3 ), p-type GBT compounds have enhanced ZT ≈ 1.4 near room temperature. *

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Section: Discussionmentioning

confidence: 99%

OptimizedZTofBi2Te3−GeTecompoun

2016

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“…The change of lattice parameters from 0 to 300 K only results in a less than 2% change in the band gap. Compared with the actual temperature dependence of band gap, 47 it seems that the temperature variation of the band gap is mainly due to lattice vibration. Figure 13 shows the variation of ␣ S along the ʈ and Ќ directions, with respect to the chemical potential , at 300 K. Apparently, the two curves are very similar, indicating the isotropy of ␣ S .…”

Section: Seebeck Coefficientmentioning

confidence: 91%

Ab initioand molecular dynamics predictions for electron and phonon transport in bismuth telluride

2008

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Phonon and electron transport in Bi 2 Te 3 has been investigated using a multiscale approach, combining the first-principles calculations, molecular dynamics ͑MD͒ simulations, and Boltzmann transport equations ͑BTEs͒. Good agreements are found with the available experimental results. The MD simulations along with the Green-Kubo autocorrelation decay method are used to calculate the lattice thermal conductivity in both the in-plane and cross-plane directions, where the required classical interatomic potentials for Bi 2 Te 3 are developed on the basis of first-principles calculations and experimental results. In the decomposition of the lattice thermal conductivity, the contributions from the short-range acoustic and optical phonons are found to be temperature independent and direction independent, while the long-range acoustic phonons dominate the phonon transport with a strong temperature and direction dependence ͑represented by a modified Slack relation͒. The sum of the short-range acoustic and optical phonon contribution is about 0.2 W / m K and signifies the limit when the long-range transport is suppressed by nanostructure engineering. The electrical transport is calculated using the full-band structure from the linearized augmented plane-wave method, BTE, and the energy-dependent relaxation-time models with the nonparabolic Kane energy dispersion. Temperature dependence of the energy gap is found to be important for the prediction of electrical transport in the intrinsic regime. Appropriate modeling of relaxation times is also essential for the calculation of electric and thermal transport, especially in the intrinsic regime. The maximum of the Seebeck coefficient appears when the chemical potential approaches the band edge and can be estimated by a simple expression containing the band gap. The scatterings by the acoustic, optical, and polar-optical phonons dominate the electrical conductivity and electric thermal conductivity.

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“…The value of *b* was considered to be close to u n ity and was determined by assuming b = 1 a t 380^K. The reason fo r th is assumption is th a t a sign re v e rs a l of th e H all e ffe c t is observed fo r the p-type specimens shown in Figure 16, and has also been observed by Shigetomi and Mori (1956), in d ic a tin g th a t b ^ 1 above 430^K, whereas S a tte rth w a ite and Ure (1957), using n-type specimens w ith low im purity content, fin d a re v e rsa l in th e H all c o e ffic ie n t, in d ic a tin g th a t b below 320^K (^ 6*4; ^6 * 5 ). I t i s seen from equations (3*4) and (3*5) th a t the Table 6-I.…”

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confidence: 98%

“…The f i r s t measurements of th e e l e c t r i c a l c o n d u c tiv ity , th e rm o e le c tric power and H a ll c o e f f i c i e n t on s in g le c r y s t a l s were made by Konorov ( 1956) over th e tem p era tu re range 300^ -^ 600^K and Shigetom i and Mori (1956) over th e range 100^ -^750^K.…”

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confidence: 99%