Anomalous temperature and disorder dependence of the electron–phonon scattering time in impure metals

The interplay between geometrical confinement and materials considerations can efficiently reduce phonon-assisted transport, enabling scattering time and dissipation engineering in quantum devices. In resonant tunneling (RT) structures, quenching of phonon-assisted transmission leading to considerable reduction of the off-resonance valley-current is shown to occur in interband devices. In structures of low dimensionality such as quantum wires, electron-phonon scattering exhibits size effects and intersubband resonances which modulates the drift velocity and conductance of one-dimensional systems. Quantum dot nanostructures offer large flexibility for reduction and modulation of dissipative processes such as oscillatory hopping conductance induced by acoustic phonons in linear chains of quantum dots or negative differential resistance curve shaping in RT through quantum dot arrays.

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Intermittent Phonon Scattering as a Possible Origin of 1/f Fluctuations in Metallic Resistors

Fluctuation and Noise Letters ◽

10.1142/s0219477515500182 ◽

2015 ◽

Vol 14 (02) ◽

pp. 1550018 ◽

Cited By ~ 3

Author(s):

Ferdinand Grüneis

Keyword(s):

Thermal Noise ◽

Phonon Scattering ◽

Phonon Modes ◽

Equilibrium Conditions ◽

Noise Component ◽

Intermittent Behavior ◽

The Mean ◽

Scattering Time ◽

Off Time ◽

Electron Phonon Scattering

We regard a metallic resistor for temperatures T ≫ Θ D (= Debye temperature); under this condition, electron–phonon scattering is the dominant scattering mechanism. We investigate the noise properties under the supposition that phonon scattering is an intermittent process. Intermissions may be caused by an interaction between different phonon modes giving rise to a short break down of a mode. Due to such an intermittent behavior, we obtain — besides thermal noise — a 1/f noise component. Under equilibrium conditions, the 1/f noise term disappears. Under an applied electric field, the electrons are accelerated between collisions resulting in an additional 1/f noise component which can be compared with Hooge's relation. The predicted Hooge coefficient is α ≈ 3 ⋅ 10-3(τ off /τs)2 with τs being the mean electron phonon scattering time and τ off being the mean off-time ( = intermission). We also find 1/f fluctuations in the square of thermal noise suggesting that an applied current only probes 1/f fluctuations which are already present under equilibrium conditions.

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Electron-phonon scattering time in crystalline disordered Ti1−xAlx alloys

Physica B Condensed Matter ◽

10.1016/0921-4526(95)00652-4 ◽

1996 ◽

Vol 219-220 ◽

pp. 68-70 ◽

Cited By ~ 1

Author(s):

J.J. Lin ◽

C.Y. Wu

Keyword(s):

Phonon Scattering ◽

Scattering Time ◽

Electron Phonon Scattering

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Evidence of a coupled electron-phonon liquid in NbGe2

Nature Communications ◽

10.1038/s41467-021-25547-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Hung-Yu Yang ◽

Xiaohan Yao ◽

Vincent Plisson ◽

Shirin Mozaffari ◽

Jan P. Scheifers ◽

...

Keyword(s):

Phonon Scattering ◽

Structural Factors ◽

Anomalous Temperature ◽

Quantum Oscillations ◽

Coordination Environment ◽

Resistivity Measurements ◽

Temperature Dependences ◽

Low Symmetry ◽

Weak Electron ◽

Electron Phonon Scattering

AbstractWhereas electron-phonon scattering relaxes the electron’s momentum in metals, a perpetual exchange of momentum between phonons and electrons may conserve total momentum and lead to a coupled electron-phonon liquid. Such a phase of matter could be a platform for observing electron hydrodynamics. Here we present evidence of an electron-phonon liquid in the transition metal ditetrelide, NbGe2, from three different experiments. First, quantum oscillations reveal an enhanced quasiparticle mass, which is unexpected in NbGe2 with weak electron-electron correlations, hence pointing at electron-phonon interactions. Second, resistivity measurements exhibit a discrepancy between the experimental data and standard Fermi liquid calculations. Third, Raman scattering shows anomalous temperature dependences of the phonon linewidths that fit an empirical model based on phonon-electron coupling. We discuss structural factors, such as chiral symmetry, short metallic bonds, and a low-symmetry coordination environment as potential design principles for materials with coupled electron-phonon liquid.

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