Nematic and superconducting order in a three-band model for the iron superconductors

AbstractThe single parabolic band (SPB) model has been widely used to preliminarily elucidate inherent transport behaviors of thermoelectric (TE) materials, such as their band structure and electronic thermal conductivity, etc. However, in the SPB calculation, it is necessary to determine some intermediate variables, such as Fermi level or the complex Fermi-Dirac integrals. In this work, we establish a direct carrier-concentration-dependent restructured SPB model, which eliminates Fermi-Dirac integrals and Fermi level calculation and emerges stronger visibility and usability in experiments. We have verified the reliability of such restructured model with 490 groups of experimental data from state-of-the-art TE materials and the relative error is less than 2%. Moreover, carrier effective mass, intrinsic carrier mobility and optimal carrier concentration of these materials are systematically investigated. We believe that our work can provide more convenience and accuracy for thermoelectric data analysis as well as instructive understanding on future optimization design.

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Manipulation of hot carrier cooling dynamics in two-dimensional Dion–Jacobson hybrid perovskites via Rashba band splitting

Nature Communications ◽

10.1038/s41467-021-24258-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jun Yin ◽

Rounak Naphade ◽

Partha Maity ◽

Luis Gutiérrez-Arzaluz ◽

Dhaifallah Almalawi ◽

...

Keyword(s):

Transient Absorption ◽

Phonon Scattering ◽

Transient Absorption Spectroscopy ◽

Band Model ◽

Two Dimensional ◽

Spintronic Devices ◽

Hot Carrier ◽

Band Splitting ◽

Perovskite Materials ◽

Spin Polarized

AbstractHot-carrier cooling processes of perovskite materials are typically described by a single parabolic band model that includes the effects of carrier-phonon scattering, hot phonon bottleneck, and Auger heating. However, little is known (if anything) about the cooling processes in which the spin-degenerate parabolic band splits into two spin-polarized bands, i.e., the Rashba band splitting effect. Here, we investigated the hot-carrier cooling processes for two slightly different compositions of two-dimensional Dion–Jacobson hybrid perovskites, namely, (3AMP)PbI4 and (4AMP)PbI4 (3AMP = 3-(aminomethyl)piperidinium; 4AMP = 4-(aminomethyl)piperidinium), using a combination of ultrafast transient absorption spectroscopy and first-principles calculations. In (4AMP)PbI4, upon Rashba band splitting, the spin-dependent scattering of hot electrons is responsible for accelerating hot-carrier cooling at longer delays. Importantly, the hot-carrier cooling of (4AMP)PbI4 can be extended by manipulating the spin state of the hot carriers. Our findings suggest a new approach for prolonging hot-carrier cooling in hybrid perovskites, which is conducive to further improving the performance of hot-carrier-based optoelectronic and spintronic devices.

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Exciton narrow band model for 7,7,8,8-tetracyanoquino-dimethane salts

Journal of the Chemical Society Faraday Transactions 2 Molecular and Chemical Physics ◽

10.1039/f29757101792 ◽

1975 ◽

Vol 71 ◽

pp. 1792

Author(s):

L. Shields

Keyword(s):

Narrow Band ◽

Band Model ◽

Narrow Band Model

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Reformulation of the MODTRAN band model for higher spectral resolution

10.1117/12.410340 ◽

2000 ◽

Cited By ~ 10

Author(s):

Alexander Berk ◽

Prabhat K. Acharya ◽

Lawrence S. Bernstein ◽

Gail P. Anderson ◽

James H. Chetwynd, Jr. ◽

...

Keyword(s):

Spectral Resolution ◽

Band Model

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IONIZATION ENERGY AND IMPURITY BAND CONDUCTION OF SHALLOW DONORS IN n-GALLIUM ARSENIDE

Canadian Journal of Physics ◽

10.1139/p67-013 ◽

1967 ◽

Vol 45 (1) ◽

pp. 119-126 ◽

Cited By ~ 24

Author(s):

J. Basinski ◽

R. Olivier

Keyword(s):

Ionization Energy ◽

Impurity Band ◽

Shallow Donor ◽

Band Model ◽

A Value ◽

Transition Concentration ◽

Temperature Electron ◽

Two Band Model ◽

Band Conduction ◽

Made In

Hall effect and resistivity measurements have been made in the temperature range 4.2–360 °K on several samples of n-type GaAs grown under oxygen atmosphere and without any other intentional dopings. The principal shallow donor in this material is considered to be Si. All samples exhibited impurity-band conduction at low temperature. Electron concentrations in the conduction band were calculated, using a two-band model, and then fitted to the usual equation expressing charge neutrality. A value of 2.3 × 10−3 eV was obtained for the ionization energy of the donors, for donor concentration ranging from 5 × 1015 cm−3 to 2 × 1016 cm−3. The conduction in the impurity band was of the hopping type for these concentrations. A value of 3.5 × 1016 cm−3 was obtained for the critical transition concentration of the impurity-band conduction to the metallic type.

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