The domain structure of GeTe as observed by electron microscopy

Snykers, M.; Delavignette, P.; Amelinckx, S.

doi:10.1016/0025-5408(72)90133-x

Cited by 60 publications

(54 citation statements)

References 2 publications

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“…When x = 0.5, impurity peaks can be observed, therefore the solubility of PbSe in rhombohedral GeTe is believed to be within 45–50%. Since the rhombohedral structure of GeTe ( a = b = c and α = β = γ < 90°) is essentially a slightly distorted rock‐salt lattice along the (111) direction, the influence on the crystal structure due to alloying can be characterized by the lattice parameters and the interaxial angles, both of which are shown in Figure b. The increase in the interaxial angle due to alloying, can be understood by the fact that PbSe crystallizes in a cubic structure.…”

Section: Resultsmentioning

confidence: 99%

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

et al. 2017

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In order to locate the optimal carrier concentrations for peaking the thermoelectric performance in p‐type group IV monotellurides, existing efforts focus on aliovalent doping, either to increase (in PbTe) or to decrease (in SnTe and GeTe) the hole concentration. The limited solubility of aliovalent dopants usually introduces insufficient phonon scattering for thermoelectric performance maximization. With a decrease in the size of cation, the concentration of holes, induced by cation vacancies in intrinsic compounds, increases rapidly from ≈1018 cm−3 in PbTe to ≈1020 cm−3 in SnTe and then to ≈1021 cm−3 in GeTe. This motivates a strategy here for reducing the carrier concentration in GeTe, by increasing the mean size of cations and vice‐versa decreasing the average size of anions through isovalent substitutions for increased formation energy of cation vacancy. A combination of the simultaneously resulting strong phonon scattering due to the high solubility of isovalent impurities, an ultrahigh thermoelectric figure of merit, zT of 2.2 is achieved in GeTe–PbSe alloys. This corresponds to a 300% enhancement in average zT as compared to pristine GeTe. This work not only demonstrates GeTe as a promising thermoelectric material but also paves the way for enhancing the thermoelectric performance in similar materials.

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Section: Resultsmentioning

confidence: 99%

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

et al. 2017

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“…This can be achieved for example, by a rhombohedral or orthorhombic distortion of the crystal structure with a displacement of atoms at the surface as shown in Fig. 4E, which is a common distortion in this class of materials (19,20,21).…”

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confidence: 99%

Observation of Dirac Node Formation and Mass Acquisition in a Topological Crystalline Insulator

Okada

Serbyn

Lin

et al. 2013

Science

290

279

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In topological crystalline insulators (TCIs), topology and crystal symmetry intertwine to create surface states with distinct characteristics. The breaking of crystal symmetry in TCIs is predicted to impart mass to the massless Dirac fermions. Here, we report high-resolution scanning tunneling microscopy studies of a TCI, Pb(1-x)Sn(x)Se that reveal the coexistence of zero-mass Dirac fermions protected by crystal symmetry with massive Dirac fermions consistent with crystal symmetry breaking. In addition, we show two distinct regimes of the Fermi surface topology separated by a Van-Hove singularity at the Lifshitz transition point. Our work paves the way for engineering the Dirac band gap and realizing interaction-driven topological quantum phenomena in TCIs.

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“…The ZT of TAGS was increased from ~1 to above 2 by increasing the composition complexity (Perumal et al, 2016). Figure 2 shows the crystal structure of TAGS in which Ag and Sb co-occupy the Ge sites in the Ge-Te lattice (Snykers et al, 1972). The decrease of thermal conductivity with increasing composition complexity is also noted.…”

Section: Multi-element Thermoelectrics In Retrospectmentioning

confidence: 96%

Multi-Principal-Element Approach to High-Performance Thermoelectric Materials

Poon

2022

Encyclopedia of Materials: Metals and Alloys

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High-entropy alloys are characterized by high configurational entropy. Since the discovery of highentropy alloys (HEA) in 2004, entropy engineering has provided a promising direction for exploiting composition, lattice disorder, band structure, and microstructure effects to advance thermoelectric performance. This review discusses the impact of entropy on thermoelectric properties and looks back at the role of multi-principal-element alloys, a weaker version of HEA, on the development of compositionally complex thermoelectric alloys in achieving high thermoelectric performance. The experimental and theoretical efforts in a wide range of material systems such as TAGS, LAST, half-Heusler, liquid-like copper chalcogenides, SnTe, and CuInTe2 chalcopyrites provide insights into the entropy engineering approach and also promise an emerging paradigm of high-entropy thermoelectrics.

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The domain structure of GeTe as observed by electron microscopy

Cited by 60 publications

References 2 publications

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

Observation of Dirac Node Formation and Mass Acquisition in a Topological Crystalline Insulator

Multi-Principal-Element Approach to High-Performance Thermoelectric Materials

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