Comparison of three structure determinations for germanium selenide, GeSe

Kannewurf, Carl R.; Kelly, A Fransted; Cashman, R. J.

doi:10.1107/s0365110x60001072

Cited by 30 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermopower measurements are consistent with p-type conductivity [3] while the sign of the Hall coefficient is reported to change from positive to negative on melting [60]. The low temperature form of crystalline GeSe, LT-GeSe, has a distorted NaCl-type structure in which each chemical species makes six bonds, three weaker than the other three, to unlike chemical species to form a double-layer structure [61][62][63][64]. At 651(5)°C it undergoes a structural phase transition to the high-temperature phase, HT-GeSe, which has a normal NaCl-type structure [65,66] before melting at 675(2)°C [67].…”

Section: Full Partial Structure Factor Analysis Of Liquid Gesesupporting

confidence: 65%

Structure of liquids and glasses in the Ge–Se binary system

Salmon

2007

Journal of Non-Crystalline Solids

104

128

View full text Add to dashboard Cite

Section: Full Partial Structure Factor Analysis Of Liquid Gesesupporting

confidence: 65%

Structure of liquids and glasses in the Ge–Se binary system

Salmon

2007

Journal of Non-Crystalline Solids

104

128

View full text Add to dashboard Cite

“…Crystallographic and microstructural parameters from a Rietveld refinement of XRD data can be found in Supporting Information Tables S1 and S2. The x = 0 sample displays an orthorhombic structure (space group Pnma , Figure b), as extensively reported for pure GeSe. − The literature data at 10% ( x = 0.1) and 20% ( x = 0.2) alloying was also confirmed, showing instead a rhombohedral R 3 m phase (Figure b). The other end member of the present research, that is at 40% alloying, displays a rock-salt cubic structure (space group Fm 3̅ m , Figure b), as described previously .…”

Section: Resultssupporting

confidence: 71%

Influence of Ge Lone Pairs on the Elasticity and Thermal Conductivity of GeSe–AgBiSe₂ Alloys

Calderón-Cueva,

Isotta,

Rylko

et al. 2023

Chem. Mater.

View full text Add to dashboard Cite

Chemical design is a compelling strategy to improve the performance of energy materials but requires a comprehensive understanding of how structure and chemistry affect materials properties. In this work, we investigate the structural, elastic, and thermal behavior of the (GeSe) 1−x −(AgBiSe 2 ) x system to shed light on the respective contributions of chemistry and crystal structure to thermal transport. In this system, progressive AgBiSe 2 alloying transforms the room-temperature structure from orthorhombic to rhombohedral to cubic rock-salt, with the latter being the thermodynamically stable phase across the entire compositional range at a high temperature. Within a given structure type, alloying progressively increases point-defect phonon scattering and decreases the speed of sound, thus reducing the lattice thermal conductivity. However, an anomalous increase in thermal conductivity is noticed upon the transition from the rhombohedral to the cubic phase, associated with a large step-like increase in the elastic moduli. Density functional theory calculations suggest this change in stiffness is due to the tendency of Ge to exhibit strongly expressed lone-pair orbitals. The lone pairs switch from fully oriented in the rhombohedral phase to randomly oriented in the cubic phase, leading to an overall bond stiffening. Supporting this argument, increased AgBiSe 2 content, and thus weakened lone-pair expression, leads to a less pronounced stiffening at the phase transition. These findings help improve our understanding of the intrinsic properties of this system and the design of rock-salt chalcogenides with tailored thermal properties.

show abstract

“…The low-temperature form of crystalline GeSe, LT-GeSe, has a distorted NaCl-type structure in which each chemical species makes six bonds, three weaker than the other three, to unlike chemical species to form a double-layer structure (Okazaki 1958, Kannewurf et al 1960, Dutta and Jeffrey 1965, Hulliger 1976). At 651(5) • C it undergoes a structural phase transition to the high-temperature phase, HT-GeSe, which has a normal NaCl-type structure (Wiedemeier andSiemers 1975, Petri et al 1999) before melting at 675(2) • C (Ipser et al 1982).…”

Section: Comparison With the High-and Low-temperature Crystal Structu...mentioning

confidence: 99%

Structure of the liquid semiconductor GeSe

Petri

Salmon

Fischer

1999

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The partial structure factors and pair distribution functions for liquid GeSe at 727(2) °C were measured by using the method of isotopic substitution in neutron diffraction. The results show that the liquid retains little memory of the high-temperature crystalline phase of GeSe. On melting, there is a reduction in the Ge-Se coordination number from 6 to 3.2(2) and both Ge-Ge and Se-Se homopolar bonds become features of the molten state with contact distances of 2.36(2) and 2.34(2) Å and coordination numbers of 0.8(1) and 0.22(3) respectively. The results are discussed by reference to the structures of molten CuSe and CuBr, which contain electronegative species of the same or similar size. The structure is also compared with that of the glass-forming network melt GeSe2 and it is found that, unlike the latter, there is no strong indication of intermediate-range atomic ordering as manifest by a prominent first sharp diffraction peak in one of the measured partial structure factors.

show abstract

Comparison of three structure determinations for germanium selenide, GeSe

Cited by 30 publications

References 0 publications

Structure of liquids and glasses in the Ge–Se binary system

Structure of liquids and glasses in the Ge–Se binary system

Influence of Ge Lone Pairs on the Elasticity and Thermal Conductivity of GeSe–AgBiSe₂ Alloys

Structure of the liquid semiconductor GeSe

Contact Info

Product

Resources

About

Comparison of three structure determinations for germanium selenide, GeSe

Cited by 30 publications

References 0 publications

Structure of liquids and glasses in the Ge–Se binary system

Structure of liquids and glasses in the Ge–Se binary system

Influence of Ge Lone Pairs on the Elasticity and Thermal Conductivity of GeSe–AgBiSe2 Alloys

Structure of the liquid semiconductor GeSe

Contact Info

Product

Resources

About

Influence of Ge Lone Pairs on the Elasticity and Thermal Conductivity of GeSe–AgBiSe₂ Alloys