Antimony as an amphoteric dopant in lead telluride

Jaworski, Christopher M.; Toboła, J.; Levin, E. M.; Schmidt‐Rohr, Klaus; Heremans, Joseph P.

doi:10.1103/physrevb.80.125208

Cited by 76 publications

(63 citation statements)

References 22 publications

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“…8,11,18 For pure PbTe (x = 0), the estimated bandgap of 0.67 eV is larger than that of the experimental measurements (∼0.2 eV), 47 but is consistent with the previous KKR-CPA result of 0.68 eV. 38 Although the magnitude of the estimated bandgap is large compared with experiment (∼0.2 eV), the trend with changing the doping concentration can be qualitatively compared.…”

supporting

confidence: 51%

“…The overall shape of the DOS for pure PbTe (x = 0) is consistent with the previous KKR-CPA results. 9,15,38 The shape of both the valence and conduction bands is not changed significantly via doping with Na, K, nor by introducing vacancies on Pb site, but the bandgap slightly increases. In all cases, the Fermi level drops into the valence band in accordance with the expected chemical effect of one hole introduced by each substitutional monovalent Na, K, Tl, or two holes for each Pb vacancy, 30 which has also been observed experimentally by low temperature Hall coefficient measurements.…”

mentioning

confidence: 99%

“…The KKR-CPA method has been successfully applied to explain experimental data in PbTe doped with both resonant and non-resonant impurities. 9,15,38,39 To test the validity of the rigid band approximation for Na-and K-doped PbTe, which has been used to explain the experimental data successfully, we calculated various amounts of doping with Na and K on Pb site, that is, up to 10% although the experimental upper limit would be less than ∼2%. 8,11,18 Furthermore, we compared with Tl-doping, which is reported to form resonant impurity states 6,9,15 in the vicinity of the valence band maximum and to exhibit superconducting properties.…”

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confidence: 99%

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Validity of rigid band approximation of PbTe thermoelectric materials

et al. 2013

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The tuning of carrier concentration through chemical doping is very important for the optimization of thermoelectric materials. Traditionally, a rigid band model is used to understand and guide doping in such semiconductors, but it is not clear whether such an approximation is valid. This letter focuses on the changes in the electronic density of states (DOS) near the valence band maximum for different p-type dopants (Na, K, Tl, or vacancy on Pb site) maintaining the high symmetry of the NaCl structure. Na- and K-doped, and vacancy-introduced PbTe show a clear rigid-band like change in DOS unlike that concluded from supercell based calculations

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Validity of rigid band approximation of PbTe thermoelectric materials

et al. 2013

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“…It must also be noted that the carrier densities for these Pb-deficit Pb0.98-xSbxTe compositions are almost one order of magnitude higher than undoped PbTe (n  1.11 x 10 -18 cm -1 ) [13], due to the aliovalent donor doping of Sb 3+ in the Pb 2+ sub-lattices of PbTe. Interestingly, Sb is known to be an amphoteric dopant depending on its lattice position [34], which means that in Te-rich PbTe, Sb substitutes for Pb (donor) and in Pb-rich PbTe, Sb substitutes for Te (acceptor). Despite PST-12 having twice the n-values of PST-8, its carrier charge mobility is reduced by half and this cumulative effect is observed in fig.…”

Section: Resultsmentioning

confidence: 99%

Enhancement in thermoelectric performance of n-type Pb-deficit Pb-Sb-Te alloys

Srinivasan

Gucci

Boussard‐Plédel

et al. 2017

Journal of Alloys and Compounds

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PbTe based materials are well known for their high performance thermoelectric properties. Here, a systematic study of thermoelectric transport properties of n-type Pb-deficit Pb0.98-xSbxTe alloys with carrier concentrations in the range of 10 -19 cm -3 is presented from room temperature to 623 K. A maximum thermoelectric figure of merit (zT) of 0.81 was achieved at 623 K for 4 mol% Sb containing Pb-deficit composition, by the cumulative integration of enhanced power factor and significant reduction in thermal conductivity. The scattering of phonons at Pb vacancies, contributed to the reduction of lattice thermal conductivity, and thereby strikingly boosted the zT of the Pb-deficit samples when compared with the pristine Pb1-xSbxTe.

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“…This is attributed to the adverse interdependence of the electrical conductivity and Seebeck coefficient via the carrier density, which proves very difficult to overcome. To achieve power factor improvements, current efforts revolve around engineering the density of states of lowdimensional materials, 2-6 modulation doping, [7][8][9][10] introducing energy resonances in the density of states, 11,12 and energy filtering in nanocomposites and superlattices. [13][14][15][16][17][18][19][20][21][22] Although theoretical works indicate that power factor improvements are possible, to-date experiments do not commonly demonstrate significant success in realizing these improvements.…”

Section: Introductionmentioning

confidence: 99%

The influence of non-idealities on the thermoelectric power factor of nanostructured superlattices

Thesberg

Pourfath

Kosina

et al. 2015

Journal of Applied Physics

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Cross-plane superlattices composed of nanoscale layers of alternating potential wells and barriers have attracted great attention for their potential to provide thermoelectric power factor improvements and higher ZT figure of merit. Previous theoretical works have shown that the presence of optimized potential barriers could provide improvements to the Seebeck coefficient through carrier energy filtering, which improves the power factor by up to 40%. However, experimental corroboration of this prediction has been extremely scant. In this work, we employ quantum mechanical electronic transport simulations to outline the detrimental effects of random variation, imperfections, and non-optimal barrier shapes in a superlattice geometry on these predicted power factor improvements. Thus, we aim to assess either the robustness or the fragility of these theoretical gains in the face of the types of variation one would find in real material systems. We show that these power factor improvements are relatively robust against: overly thick barriers, diffusion of barriers into the body of the wells, and random fluctuations in barrier spacing and width. However, notably, we discover that extremely thin barriers and random fluctuation in barrier heights by as little as 10% is sufficient to entirely destroy any power factor benefits of the optimized geometry. Our results could provide performance optimization routes for nanostructured thermoelectrics and elucidate the reasons why significant power factor improvements are not commonly realized in superlattices, despite theoretical predictions. V C 2015 AIP Publishing LLC.

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Antimony as an amphoteric dopant in lead telluride

Cited by 76 publications

References 22 publications

Validity of rigid band approximation of PbTe thermoelectric materials

Validity of rigid band approximation of PbTe thermoelectric materials

Enhancement in thermoelectric performance of n-type Pb-deficit Pb-Sb-Te alloys

The influence of non-idealities on the thermoelectric power factor of nanostructured superlattices

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