High thermoelectric performance by chemical potential tuning and lattice anharmonicity in GeTe1−xIx compounds

2021 ◽  
Author(s):  
Song Yi Back ◽  
Jae Hyun Yun ◽  
Hyunyong Cho ◽  
Seokyeong Byeon ◽  
Hyungyu Jin ◽  
...  
Keyword(s):  
Chemical Potential ◽  
Reference Data ◽  
Thermoelectric Performance ◽  
Temperature Dependent ◽  
Black Line ◽  
Β Phase ◽  
Red Line

Electronic ZT value with chemical potential for rhombohedral α- (black line) and cubic β-phase (red line) (a) and the temperature-dependent ZT value of GeTe1−xIx compounds with reference data (b).

High thermoelectric performance in low-cost SnS0.91Se0.09 crystals

Science ◽  
2019 ◽  
Vol 365 (6460) ◽  
pp. 1418-1424 ◽  
Author(s):  
Wenke He ◽  
Dongyang Wang ◽  
Haijun Wu ◽  
Yu Xiao ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Thermoelectric Materials ◽  
High Performance ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Toxic Elements ◽  
Low Cost ◽  
Thermoelectric Performance ◽  
Tin Sulfide ◽  
Temperature Dependent ◽  
Earth Abundant

Thermoelectric technology allows conversion between heat and electricity. Many good thermoelectric materials contain rare or toxic elements, so developing low-cost and high-performance thermoelectric materials is warranted. Here, we report the temperature-dependent interplay of three separate electronic bands in hole-doped tin sulfide (SnS) crystals. This behavior leads to synergistic optimization between effective mass (m*) and carrier mobility (μ) and can be boosted through introducing selenium (Se). This enhanced the power factor from ~30 to ~53 microwatts per centimeter per square kelvin (μW cm−1 K−2 at 300 K), while lowering the thermal conductivity after Se alloying. As a result, we obtained a maximum figure of merit ZT (ZTmax) of ~1.6 at 873 K and an average ZT (ZTave) of ~1.25 at 300 to 873 K in SnS0.91Se0.09 crystals. Our strategy for band manipulation offers a different route for optimizing thermoelectric performance. The high-performance SnS crystals represent an important step toward low-cost, Earth-abundant, and environmentally friendly thermoelectrics.

Local chemical potential, local hardness, and dual descriptors in temperature dependent chemical reactivity theory

2017 ◽  
Vol 19 (21) ◽  
pp. 13687-13695 ◽  
Author(s):  
Marco Franco-Pérez ◽  
Paul W. Ayers ◽  
José L. Gázquez ◽  
Alberto Vela
Keyword(s):  
Chemical Potential ◽  
Chemical Reactivity ◽  
Potential Well ◽  
Temperature Dependent ◽  
Local Hardness ◽  
Chemical Reactivity Theory ◽  
Definition Of

From the definition of a local chemical potential, well-behaved expressions for the local hardness and the dual descriptors are derived.

X-ray study of the α–β transformation of berlinite (AlPO4)

1976 ◽  
Vol 54 (6) ◽  
pp. 638-647 ◽  
Author(s):  
H. N. Ng ◽  
C. Calvo
Keyword(s):  
Room Temperature ◽  
Translational Motion ◽  
Fold Axis ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Atomic Displacements ◽  
Β Phase ◽  
Four Corners ◽  
Dauphiné Twinning

The α–β transformation of berlinite (AlPO4) at 586 °C was studied by X-ray diffraction. Atomic displacements were obtained from results of least-squares refinement of data taken between room temperature and 600 °C using reflections whose intensity is unaffected by Dauphiné twinning. The results suggest a rotational motion of the PO4 and AlO4 tetrahedra around the two-fold axis together with a translational motion along the same axis as the transition is approached from below. The vibrational amplitudes of the atoms increase with temperature and have exceeded half of the separation between Dauphiné twin-related configurations at 500 °C. The final β-phase configuration is not achieved by this twinning due to the mismatch of the two configurational potential minima in the a direction. Analysis of the intensity vs. temperature data favours a single minimum model for the β phase configuration over an order–disorder model. The β-AlPO4 structure consists of alternate PO4 and AlO4 tetrahedra sharing all four corners with P—O and Al—O distances 1.505 and 1.694 Å respectively. The results are correlated with those obtained from temperature dependent studies by Raman scattering and by EPR on Fe3+-doped AlPO4.

Aspects of Electronic Structure Instability in Search for New Superconductors: Superconducting Boride at Liquid Nitrogen Temperature?

2008 ◽  
Vol 73 (6-7) ◽  
pp. 795-810 ◽  
Author(s):  
Pavol Baňacký
Keyword(s):  
Electronic Structure ◽  
Critical Temperature ◽  
State Transition ◽  
Chemical Potential ◽  
Liquid Nitrogen Temperature ◽  
Temperature Dependent ◽  
Nuclear Dynamics ◽  
Electron Phonon Coupling ◽  
Superconducting Compounds ◽  
Oppenheimer Approximation

It has been shown that electron-phonon coupling in superconductors induces temperature-dependent electronic structure instability which is related to fluctuation of analytic critical point of some bands across the Fermi level. The band fluctuation results in a considerable reduction of chemical potential and to breakdown of the adiabatic Born-Oppenheimer approximation. At critical temperature Tc, superconducting system undergoes transition from the adiabatic electronic ground state into the antiadiabatic state at broken symmetry, which is stabilized due to the effect of nuclear dynamics. This effect is absent in non-superconducting compounds. In a good agreement with the experimental Tc of superconducting state transition, the critical temperature of the adiabatic ↔ antiadiabatic state transition has been calculated for three different superconductors. Two hypothetical compounds, LiB and ZnB2, are predicted to be potential superconductors with Tc about 17 and 77.5 K, respectively.

GIBBS ADSORPTION ISOTHERM FOR CONCENTRATION AS VARIABLE

2005 ◽  
Vol 12 (03) ◽  
pp. 379-389
Author(s):  
SHIMIN ZHANG
Keyword(s):  
Adsorption Isotherm ◽  
Chemical Potential ◽  
Multicomponent System ◽  
Liquid Interface ◽  
Dilute Solution ◽  
Independent Variables ◽  
Β Phase ◽  
Application Condition ◽  
Dividing Surface ◽  
Solid Liquid

Gibbs adsorption isotherm of the multicomponent system for concentration instead of chemical potential as independent variables is deduced and explained in a simple way. For the multicomponent system composed of α and β phases with plane interface, if the β phase is a dilute solution, and component k is solvent as well as [Formula: see text], Gibbs adsorption isotherm of component i can be expressed as [Formula: see text] (the dividing surface is placed where the adsorption of component k is zero). The adsorption of some components on the vapor–liquid interface of dilute solution with moderate or low pressure can meet the application condition of this adsorption isotherm. The adsorption of various components on the solid–liquid and liquid–liquid interface of dilute solution can also meet the application condition of this adsorption isotherm if various components of one phase are virtually insoluble in another phase.

Effect of Next-Nearest-Neighbor Electron Hopping on Superconducting Gap of Cuprate Superconductors

SPIN ◽  
2019 ◽  
Vol 09 (03) ◽  
pp. 1950016
Author(s):  
Pratima Beura ◽  
Kamal L. Mohanta
Keyword(s):  
Cuprate Superconductors ◽  
Nearest Neighbor ◽  
Chemical Potential ◽  
Coupling Parameter ◽  
Pairing Symmetry ◽  
Function Technique ◽  
Superconducting Gap ◽  
Temperature Dependent ◽  
Electron Hopping ◽  
Grid Points

We study here a single band Hamiltonian model to describe the effect of next-nearest-neighbor (NNN) electron hopping on superconducting gap in Cuprates. The Hamiltonian consists of nearest-neighbor (NN) and next-nearest-neighbor (NNN) electron hopping integrals between the copper sides. By taking d-wave pairing symmetry into account, BCS type superconducting interaction is studied. By applying Zubarev’s Green function technique, the total Hamiltonian is solved. From the correlation function, the temperature-dependent superconducting gap (SC) equation is derived and is computed self-consistently by using technique [Formula: see text] grid points of the electron momentum. By varying SC coupling, chemical potential, J-T coupling parameter and second-nearest-neighbor electron hopping integral, the evolution of the order parameter is investigated.

Hand-List of Islamic Manuscripts acquired by the India Office Library, 1936–8

1939 ◽  
Vol 71 (3) ◽  
pp. 353-396
Author(s):  
A. J. Arberry
Keyword(s):  
Black Line ◽  
Blue Line ◽  
Red Line

This manuscript is written in the rather inelegant “Bihari” hand, which C. Stewart quite properly described as “a branch of the Cufick”. The scribe has used a curious colour-scheme for each page, writing line 1 in blue, line 2 in red, lines 3–6 in black, line 7 in red, line 8 in blue, line 9 in red, lines 10–13 in black, line 14 in red, and line 15 in blue: the garish effect is further accentuated by the use of gilt ornaments to mark the verses, sections, etc., and by a minute Persian interlineary translation in red ink. There are rather crude ornamental panels on foil. 1–2, 199–200 (beginning of S. xix), and 412–13. The pages are somewhat damaged by damp, and some have been torn and inexpertly mended. The binding is Indian, of about 1830.

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