Adiabatic bond charge model for the phonons in diamond, Si, Ge, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi><mml:mo>−</mml:mo><mml:mi mathvariant="normal">Sn</mml:mi></mml:math>

Weber, W.

doi:10.1103/physrevb.15.4789

Cited by 710 publications

(222 citation statements)

References 33 publications

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“…The existence of dipole moment for those elemental crystals can be described formally by a shell model [138]. Unfortunately, for numeric calculation, shell model is not too suitable to calculate IR and Raman spectra: unrealistic parameters must be used for obtaining the observed intensity [139,140]. Adiabatic bond charge model is a more realistic model for optical spectra of semiconductors [141].…”

Section: Gap Problemmentioning

confidence: 99%

Electronic structures and mechanical properties of boron and boron-rich crystals (Part I)

Shirai

2010

J. Superhard Mater.

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Section: Gap Problemmentioning

confidence: 99%

Electronic structures and mechanical properties of boron and boron-rich crystals (Part I)

Shirai

2010

J. Superhard Mater.

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“…where q ¼ k 1 À k 2 is the phonon wave vector, ¼ AE are the position vectors of the two basis atoms, Ák ¼ k 1 þ g 1 À k 2 À g 2 , is the silicon density, and @ q and q; are the phonon energy and the polarization vector for the th atom, obtained here from the adiabatic bond-charge model [17]. For the Elliott processes v ¼ v n , while for Yafet processes v ¼ v so in Eq.…”

Section: :431 #mentioning

confidence: 99%

“…We introduce a pseudopotential model that reproduces the known spin-orbit splittings of the relevant electronic states. The model, together with a realistic phonon structure taken from the adiabatic bond-charge model [17], allows us to calculate the spin mixing probabilities and the electron-phonon-induced spin flips for both the Elliott and Yafet processes. We show that the interference between the two processes affects T 1 over a remarkably wide temperature range.…”

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confidence: 99%

Theory of the Spin Relaxation of Conduction Electrons in Silicon

2010

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A realistic pseudopotential model is introduced to investigate the phonon-induced spin relaxation of conduction electrons in bulk silicon. We find a surprisingly subtle interference of the Elliott and Yafet processes affecting the spin relaxation over a wide temperature range, suppressing the significance of the intravalley spin-flip scattering, previously considered dominant, above roughly 120 K. The calculated spin relaxation times T 1 agree with the spin resonance and spin injection data, following a T À3 temperature dependence. The valley anisotropy of T 1 and the spin relaxation rates for hot electrons are predicted. DOI: 10.1103/PhysRevLett.104.016601 PACS numbers: 72.25.Rb, 72.25.Dc, 76.30.Pk Silicon is the core material for the information technology. Yet we know surprisingly little about the spin relaxation processes of its conduction electrons [1,2]. With the pioneering demonstration of the spin injection into silicon by Appelbaum et al. [3,4] and related experimental breakthroughs [5,6] and steps towards silicon spintronics [7], as well as with theoretical analyses [8-10], we have gained valuable new insight into the spin transport and relaxation in this material.A systematic investigation of the conduction electron spin relaxation time T 1 in silicon was conducted earlier by Lépine [11] using electron spin resonance (ESR) (see the summary in Ref.[2]). As the ESR does not discriminate between conduction electrons and electrons bound on donors, the representative data are limited to temperatures above T % 150 K at which most electrons are in the conduction band for the investigated donor densities [11]. Spin injection, on the other hand, looks at conduction electrons only. Appelbaum et al. [3,6] extracted useful data below 150 K, filling the gap. These measurements were made using samples with nondegenerate electron densities. The conduction electron spin relaxation and spin transport properties were also investigated in Si=SiGe quantum wells [10,12]. There, however, the spin coherence is due, not to the bulk-derived properties, but rather to the appearance of the structure-inversion anisotropy spin-orbit fields.While it is generally believed that the spin relaxation in silicon is caused by the Elliott-Yafet mechanism [2,3,6,11,13] (unlike in III-V semiconductors, in which the most important mechanism is the D'yakonov-Perel' one [14]) there is as yet no systematic theoretical study of it. There are two processes involved: that of Elliott and that of Yafet. In the Elliott processes [15] the spin flip is due to the admixture of the Pauli up and down spins in the Bloch state, caused by spin-orbit coupling. The electronphonon matrix element couples only equal Pauli spins. In the Yafet processes [13] spin flips are due to the phononmodulated spin-orbit coupling so that the electron-phonon coupling alone couples opposite spins. The two processes interfere destructively at low phonon momenta affecting T 1 typically at very low temperatures [13]. Yafet gave qualitative estimates for T 1 in silicon assuming...

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“…For a given value of k one can construct a force constant matrix 26 using second-order derivative of the potential function, the eigen vectors of the force constant matrix then give P and the eigen values scaled with atomic mass give ω Figure 3 shows the relaxation time for the transverse and longitudinal phonons as obtained for the bulk case. The phonon density of states (PDOS) was computed by taking the FFT of the function C(t) 25 given as…”

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confidence: 99%

Akhiezer damping in nanostructures

Kunal

Aluru

2011

Phys. Rev. B

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Dissipation in a nano-mechanical resonator under the application of a nearly uniform strain field is investigated using Molecular Dynamics (MD) simulations. Under the application of a uniform strain field and in the frequency range studied, we expect Akhiezer damping to be the dominant loss mechanism. The scaling of energy dissipation rate with frequency for the bulk case and a finite sized nanostructure are studied and the results are explained by Akhiezer damping. The size effect on the dissipation rate is also investigated. The results show a significant role of the surface on the dissipation rate. An increase in the Q factor with a decrease in thickness of the structure is observed for a certain range. Below some critical thickness, the trend reverses indicating multiple roles of the surface contributing to the dissipation process.

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Adiabatic bond charge model for the phonons in diamond, Si, Ge, andα−Sn

Cited by 710 publications

References 33 publications

Electronic structures and mechanical properties of boron and boron-rich crystals (Part I)

Electronic structures and mechanical properties of boron and boron-rich crystals (Part I)

Theory of the Spin Relaxation of Conduction Electrons in Silicon

Akhiezer damping in nanostructures

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