<i>Ab initio</i>Method for Calculating Electron-Phonon Scattering Times in Semiconductors: Application to GaAs and GaP

Sjakste, Jelena; Vast, Nathalie; Tyuterev, V. G.

doi:10.1103/physrevlett.99.236405

Cited by 68 publications

(65 citation statements)

References 30 publications

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“…These calculations yielded previously unknown scattering and transport parameters that were used to predict the mobility in strained Ge 19 and strained SiGe alloys. 16 Similar ab initio methods have also been used to calculate the electron-phonon scattering parameters in Ge, 20 GaAs, and GaP, 21 with excellent agreement with experiments.…”

Section: Introductionmentioning

confidence: 94%

Giant piezoresistance in silicon-germanium alloys

Murphy-Armando

Fahy

2012

Phys. Rev. B

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Type of publicationArticle (peer-reviewed) We use first-principles electronic structure methods to show that the piezoresistive strain gauge factor of single-crystalline bulk n-type silicon-germanium alloys at carefully controlled composition can reach values of G = 500, three times larger than that of silicon, the most sensitive such material used in industry today. At cryogenic temperatures of 4 K we find gauge factors of G = 135 000, 13 times larger than that observed in Si whiskers. The improved piezoresistance is achieved by tuning the scattering of carriers between different ( and L) conduction band valleys by controlling the alloy composition and strain configuration.

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Section: Introductionmentioning

confidence: 94%

Giant piezoresistance in silicon-germanium alloys

Murphy-Armando

Fahy

2012

Phys. Rev. B

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“…Thus, electron-phonon scattering is the dominant mechanism by which equilibrium is established between the chemical potentials in the electron and hole bands. Because of the very low density of electron states near the conduction and valence band edges in Bi, we expect this process is substantially slower than, for example, Γ − L intervalley scattering in Ge or GaAs 17,18 .…”

Section: Introductionmentioning

confidence: 99%

“…the scattering of carriers from one valley to another) involves a change in carrier momentum comparable to the size of the Brillouin Zone and is dominated by electron-phonon scattering 8 . Typical intervalley scattering times are of the order of a few hundred fs but this depends strongly on the relative energy of the band extrema and density of states in different valleys 17,18 . 3.…”

Section: Introductionmentioning

confidence: 99%

Free-carrier relaxation and lattice heating in photoexcited bismuth

et al. 2013

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We report ultrafast surface pump and interface probe experiments on photoexcited carrier transport across single crystal bismuth films on sapphire. The film thickness is sufficient to separate carrier dynamics from lattice heating and strain, allowing us to investigate the time-scales of momentum relaxation, heat transfer to the lattice and electron-hole recombination. The measured electron-hole (e − h) recombination time is 12-26 ps and ambipolar diffusivity is 18-40 cm 2 /s for carrier excitation up to ∼ 10 19 cm −3 . By comparing the heating of the front and back sides of the film, we put lower limits on the rate of heat transfer to the lattice, and by observing the decay of the plasma at the back of the film, we estimate the timescale of electron-hole recombination. We interpret each of these timescales within a common framework of electron-phonon scattering and find qualitative agreement between the various relaxation times observed. We find that the carrier density is not determined by the e − h plasma temperature after a few picoseconds. The diffusion and recombination become nonlinear with initial excitation > ∼ 10 20 cm −3 .

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“…At the same time, ab initio calculations provide an effective tool to estimate electron-phonon coupling strength in metals [10][11][12] and semimetals like graphene [13][14][15][16] or bismuth 17,18 . In the case of semiconductors, the predictive capability of calculations based on density functional perturbation theory (DFPT) 19,20 for the electronphonon matrix elements has been demonstrated in a number of semiconductors [21][22][23] , alloys 24,25 and nanostructures 23,26 . Recently, a method to interpolate the electron-phonon coupling matrix elements using Wannier fuctions has been introduced 11,27,28 , providing a computationally efficient method to calculate electron-phonon matrix elements on extremely fine grids in the Brillouin zone (BZ) of metals.…”

Section: Introductionmentioning

confidence: 99%

Wannier interpolation of the electron-phonon matrix elements in polar semiconductors: Polar-optical coupling in GaAs

et al. 2015

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We generalize the Wannier interpolation of the electron-phonon matrix elements to the case of polar-optical coupling in polar semiconductors. We verify our methodological developments against experiments, by calculating the widths of the electronic bands due to electron-phonon scattering in GaAs, the prototype polar semiconductor. The calculated widths are then used to estimate the broadenings of excitons at critical points in GaAs and the electron-phonon relaxation times of hot electrons. Our findings are in good agreement with available experimental data. Finally, we demonstrate that while the Fröhlich interaction is the dominant scattering process for electrons/holes close to the valley minima, in agreement with low-field transport results, at higher energies, the intervalley scattering dominates the relaxation dynamics of hot electrons or holes. The capability of interpolating the polar-optical coupling opens new perspectives in the calculation of optical absorption and transport properties in semiconductors and thermoelectrics.

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Ab initioMethod for Calculating Electron-Phonon Scattering Times in Semiconductors: Application to GaAs and GaP

Cited by 68 publications

References 30 publications

Giant piezoresistance in silicon-germanium alloys

Giant piezoresistance in silicon-germanium alloys

Free-carrier relaxation and lattice heating in photoexcited bismuth

Wannier interpolation of the electron-phonon matrix elements in polar semiconductors: Polar-optical coupling in GaAs

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