Origin of Saturation Effects in Electron Transport

Côté, Paul J.; Meisel, L. V.

doi:10.1103/physrevlett.40.1586

Cited by 127 publications

(29 citation statements)

References 20 publications

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“…It is then natural to look for extensions of the Boltzmann equations, which would extend the range of perturbation strengths that can be treated. 5,6 We find, however, that in, e.g., the A15 compounds the thermally excited phonons even at relatively small T tend to largely remove the effects of periodicity. In the semiclassical treatment of the phonons, the momentum conservation in the electronic system is lost already for temperatures of the order of a few hundred K. We therefore consider the opposite limit to the Boltzmann equation, where we assume that thermal excitations have completely destroyed periodicity.…”

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confidence: 64%

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Electrical resistivity at large temperatures: Saturation and lack thereof

Calandra

Gunnarsson

2002

Phys. Rev. B

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Many transition metal compounds show a saturation of the electrical resistivity at high temperatures, T , while the alkali-doped fullerenes and the high-Tc cuprates are usually considered to show no saturation. We present a model of transition metal compounds, which shows saturation, and a model of alkali-doped fullerenes, which shows no saturation. The electron scattering is assumed to be due to interaction with phonons. The properties of these models are determined by performing quantum Monte-Carlo calculations. To analyze the results, as well as earlier results for the high-Tc cuprates, we use the f-sum rule. We demonstrate that the f-sum rule leads to a natural upper limit for the resistivity at large T . For some systems and at low T , the resistivity increases so rapidly that this upper limit is approached for experimentally accessible temperatures. The resistivity then saturates. For a model of transition metal compounds with weakly interacting electrons, the upper limit corresponds to an apparent mean free path consistent with the Ioffe-Regel condition. For a model of the high Tc cuprates with strongly interacting electrons, however, the upper limit is much larger than the Ioffe-Regel condition suggests. This upper limit is not exceeded by experimental resistivities. The experimental data for the cuprates are therefore consistent with saturation. After saturation the resistivity normally grows slowly. The alkali-doped fullerenes can be considered as systems where saturation has happened already for T = 0, due to orientational disorder. We show, however, that for these systems the resistivity grows so rapidly after "saturation" that this concept is meaningless. This is due both to the small band width and to the coupling to the level energies of the important (intramolecular) phonons in the fullerenes.

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confidence: 64%

“…4 A proper theory of saturation is therefore needed. A number of theories have been put forward, [5][6][7] but no theory has been generally accepted. Due to the break-down of the semiclassical theory when l ∼ d, the concept of a mean free path itself becomes questionable for such small values of l. In this case we use Eq.…”

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confidence: 99%

Electrical resistivity at large temperatures: Saturation and lack thereof

Calandra

Gunnarsson

2002

Phys. Rev. B

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“…In the case where the dependence of the G function upon the contact resistance R0 remains the same as in the case of the clean orifice, the T-model is applicable. In the latter case T = (Gapp .... t/Gexact) 2 (23) In the opposite situation, which evidences itself experimentally as a lack of dependence of the quantity V2/V~ on the value of R0, we have the case of a dirty contact.…”

Section: Spectral Line Intensitiesmentioning

confidence: 98%

Point-contact spectroscopy of electron-phonon interaction in normal-metal single crystals

1981

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Recent studies of the phonon spectra of metals using "point-contact spectroscopy" (PCS) are reviewed, with particular emphasis on the possibility of studying the electron-phonon interaction in single crystals. Various regimes of current flow in contacts are discussed, including ballistic, diffusion, and thermal regimes. The former (the Knudsen limiO proves to be the most appropriate for spectroscopic purposes; the PC spectrum (the derivative dZV/dI 2) in this case reveals a complicated structure containing information about singular points of the phonon density of states as well as the anisotropy (and energy dependence) of matrix elements of the electron-phonon interaction. Experimental results are presented for Cu, the most suitable metal for obtaining contacts of sufficiently good quality. The origins of the PC spectrum background at high energies and the singularities of PC spectra at low energy are analyzed. They are attributed to the nonequilibrium phonons reabsorbed in the junction, and to the influence of electron-impurity scattering upon the effectiveness of electron-phonon collisions.

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“…Laughlin (1982) presented a theory where exchange interaction reduced the density of states and increased the Fermi velocity in such a way that resistivity saturation was obtained. Cote and Meisel (1978) and Morton et al (1978) proposed that an electron is only scattered by a phonon if the mean free path of the electron is longer than the phonon wave length. As T is increased and l becomes shorter, an increasing number of phonons become inefficient scatters.…”

Section: Early Theoretical Workmentioning

confidence: 99%

Colloquium: Saturation of electrical resistivity

Calandra²,

2003

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Resistivity saturation is observed in many metallic systems with large resistivities, i.e., when the resistivity has reached a critical value, its further increase with temperature is substantially reduced. This typically happens when the apparent mean free path is comparable to the interatomic separations -the Ioffe-Regel condition. Recently, several exceptions to this rule have been found. Here, we review experimental results and early theories of resistivity saturation. We then describe more recent theoretical work, addressing cases both where the Ioffe-Regel condition is satisfied and where it is violated. In particular we show how the (semiclassical) Ioffe-Regel condition can be derived quantum-mechanically under certain assumptions about the system and why these assumptions are violated for high-Tc cuprates and alkali-doped fullerides.

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Origin of Saturation Effects in Electron Transport

Cited by 127 publications

References 20 publications

Electrical resistivity at large temperatures: Saturation and lack thereof

Electrical resistivity at large temperatures: Saturation and lack thereof

Point-contact spectroscopy of electron-phonon interaction in normal-metal single crystals

Colloquium: Saturation of electrical resistivity

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