Conductivity and thermopower of heavy fermion systems with disorder

Grenzebach, Claas; Czycholl, Gerd

doi:10.1016/j.physb.2005.01.209

Cited by 8 publications

(5 citation statements)

References 6 publications

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“…This is usually interpreted as a signature of strong correlations [21]. Theoretical investigations of the Seebeck coefficient in strongly correlated semiconductors predict large peaks at temperatures which are fractions (∼ 0.05) of ε g [4][5][6], in reasonable agreement with experiments on FeSi [5].…”

supporting

confidence: 70%

“…During the past two decades correlated semiconductors and Kondo insulators containing rare-earth, actinide or transition-metal atoms have received renewed attention [1,2]. They are characterised by a small hybridisation gap at the Fermi level from mixing of a broad conduction band with a narrow d-or f -band [1,2] and are expected to have large absolute values of Seebeck coefficient (S) [3][4][5][6]. Experimentally, |S| ∼ 500-1000 µVK −1 has been observed at some characteristic temperatures below 300 K [7][8][9] and up to now correlated semiconductors have only showed moderately enhanced thermoelectric properties.…”

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confidence: 99%

“…This favours a large thermoelectric power factor [3]. Theoretically, strongly correlated semiconductors have been treated by dynamical mean-field theory using the periodic Anderson model [13], and recently calculations of S have appeared [4][5][6]. Though these results are model dependent it has been shown that a large S combined with reasonably low ρ is possible at low temperatures [4].…”

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confidence: 99%

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Colossal Seebeck coefficient in strongly correlated semiconductor FeSb ₂

et al. 2007

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For more than a decade strongly correlated semiconductors and Kondo insulators have been considered as potential thermoelectric materials. Such materials have large d-or f -character of the electronic band structure close to the Fermi level that theoretically leads to Seebeck coefficients (S) with large magnitudes. In this work it is shown for the first time that the strongly correlated semiconductor FeSb2 exhibits a colossal Seebeck coefficient of ∼ −45000 µVK −1 at 10 K. The thermoelectric power factor P F = S 2 • ρ −1 , where ρ is the electrical resistivity, reaches a record high value of ∼ 2300 µWK −2 cm −1 at 12 K and is 65 times larger than that of the state-of-the-art Bi2Te3-based thermoelectric materials. However, due to a large lattice thermal conductivity the dimensionless thermoelectric figure of merit is only 0.005 at 12 K. Nonetheless, the potential of FeSb2 as a future solid-state thermoelectric cooling device at cryogenic temperatures is underlined.

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Colossal Seebeck coefficient in strongly correlated semiconductor FeSb ₂

et al. 2007

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“…Since these materials have efficiency for converting temperature differences in electric voltages, it could be used to make refrigerators or power generators [1]. Correlated semiconductors and Kondo insulators containing rare-earth or transition metal atoms have been regarded as the possible candidates for good thermoelectric materials due to a sharp singularity in the density of states very near to the chemical potential [2][3][4][5].…”

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confidence: 99%

Study for material analogs of FeSb2 : Material design for thermoelectric materials

Kang

Kotliar

2018

Phys. Rev. Materials

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Using the ab initio evolutionary algorithm (implemented in USPEX) and electronic structure calculations we investigate the properties of a new thermoelectric material FeSbAs, which is a material analog of the enigmatic thermoelectric FeSb2. We utilize the density functional theory and the Gutzwiller method to check the energetics. We find that FeSbAs can be made thermodynamically stable above ∼30 GPa. We investigate the electronic structure and thermoelectric properties of FeSbAs based on the density functional theory and compare with those of FeSb2. Above 50 K, FeSbAs has higher Seebeck coefficients than FeSb2. Upon doping, the figure of merit becomes larger for FeSbAs than for FeSb2. Another material analog FeSbP, was also investigated, and found thermodynamically unstable even at very high pressure. Regarding FeSb2 as a member of a family of compounds (FeSb2, FeSbAs, and FeSbP) we elucidate what are the chemical handles that control the gaps in this series. We also investigate solubility (As or P for Sb in FeSb2) we found As to be more soluble. Finally, we study a two-band model for thermoelectric properties and find that the temperature dependent chemical potential and the presence of the ionized impurities are important to explain the extremum in the Seebeck coefficient exhibited in experiments for FeSb2.PACS numbers:

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“…The low-temperature state is a semiconductor with an extremely narrow indirect band gap, which promotes strong correlation effects between d and conduction-band states. [6][7][8][9] The minimum direct gap value extracted from reflectivity measurements 10,11 ranges between 30 and 40 meV. Recent band-structure calculations 12 have shown that it is possible to properly describe the indirect semiconducting gap of FeSb 2 by going beyond standard density functional theory (DFT) methods for instance using GW calculations.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic, thermoelectric, and magnetic properties of FeSb2: A combined first-principles and experimental study

et al. 2011

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We analyze the thermodynamic, magnetic, and transport properties of the narrow band-gap semiconductor FeSb 2 using density functional theory calculations corroborated by nuclear inelastic spectroscopy and ultrasound experiments. The vibrational properties (phonon spectrum, density of states, heat capacity) and elastic constants are computed through response function calculations and are in good agreements with the measurements. The electron-phonon coupling effects are also studied. The estimations of linewidth broadening due to electron-phonon coupling along the high-symmetry directions in the first Brillouin zone are given. The linewidth broadening reaches the largest value for Fe optical modes in the vicinity of the X[0.5,0,0] point. The broadening, when compared to those obtained at the other symmetry points, differs by up to two orders of magnitude. From the Boltzmann theory applied to our electronic band structure, we investigate the electrical transport properties. It is found that a purely electronic structure description is incompatible with the record value of the Seebeck coefficient experimentally observed at T ≈ 12 K. The diamagnetic to paramagnetic crossover at a temperature around 100 K is also described from the calculation of the magnetic susceptibility, and results compare well with experiment.

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Conductivity and thermopower of heavy fermion systems with disorder

Cited by 8 publications

References 6 publications

Colossal Seebeck coefficient in strongly correlated semiconductor FeSb ₂

Colossal Seebeck coefficient in strongly correlated semiconductor FeSb ₂

Study for material analogs of FeSb2 : Material design for thermoelectric materials

Thermodynamic, thermoelectric, and magnetic properties of FeSb2: A combined first-principles and experimental study

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Conductivity and thermopower of heavy fermion systems with disorder

Cited by 8 publications

References 6 publications

Colossal Seebeck coefficient in strongly correlated semiconductor FeSb 2

Colossal Seebeck coefficient in strongly correlated semiconductor FeSb 2

Study for material analogs of FeSb2 : Material design for thermoelectric materials

Thermodynamic, thermoelectric, and magnetic properties of FeSb2: A combined first-principles and experimental study

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Product

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Colossal Seebeck coefficient in strongly correlated semiconductor FeSb ₂

Colossal Seebeck coefficient in strongly correlated semiconductor FeSb ₂