Phonon-limited mean free path in the Sondheimer oscillation of aluminum

Sato, Hideyuki

doi:10.1007/bf00114325

“…Key to observable SO is that electrons do not undergo large-angle scattering events on their path between the surfaces. We therefore have the condition that l MR > d 36 , 37 . As l MR ( T ) decreases with increasing temperature and the boundary scattering is assumed to be temperature-independent, the SO amplitude is suppressed as which allows us to estimate the bulk transport mean free path within a finite-size sample, even when d ≪ l MR .…”

Section: Discussionmentioning

confidence: 99%

“…As l MR ( T ) decreases with increasing temperature and the boundary scattering is assumed to be temperature-independent, the SO amplitude is suppressed as which allows us to estimate the bulk transport mean free path within a finite-size sample, even when d ≪ l MR . It is extracted as 36 : where A ( T ) is the SO amplitude at temperature T . A ( T = 0) is estimated by extrapolation, which is a robust procedure as the SO amplitude saturates at low but finite temperatures.…”

Section: Discussionmentioning

confidence: 99%

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Sondheimer oscillations as a probe of non-ohmic flow in WP2 crystals

Delft

¹

,

Wang

²

,

Putzke

³

et al. 2021

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As conductors in electronic applications shrink, microscopic conduction processes lead to strong deviations from Ohm’s law. Depending on the length scales of momentum conserving (lMC) and relaxing (lMR) electron scattering, and the device size (d), current flows may shift from ohmic to ballistic to hydrodynamic regimes. So far, an in situ methodology to obtain these parameters within a micro/nanodevice is critically lacking. In this context, we exploit Sondheimer oscillations, semi-classical magnetoresistance oscillations due to helical electronic motion, as a method to obtain lMR even when lMR ≫ d. We extract lMR from the Sondheimer amplitude in WP2, at temperatures up to T ~ 40 K, a range most relevant for hydrodynamic transport phenomena. Our data on μm-sized devices are in excellent agreement with experimental reports of the bulk lMR and confirm that WP2 can be microfabricated without degradation. These results conclusively establish Sondheimer oscillations as a quantitative probe of lMR in micro-devices.

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“…Key to observable SO is that electrons do not undergo large-angle scattering events on their path between the surfaces. We therefore have the condition that l MR > d 36,37 . As l MR (T ) decreases with increasing temperature and the boundary scattering is assumed to be temperature-independent, the SO amplitude is suppressed as e −d/l MR (T ) which allows us to estimate the bulk transport mean-free-path within a finite-size sample, even when d l MR .…”

Section: Provides Viamentioning

confidence: 99%

“…As l MR (T ) decreases with increasing temperature and the boundary scattering is assumed to be temperature-independent, the SO amplitude is suppressed as e −d/l MR (T ) which allows us to estimate the bulk transport mean-free-path within a finite-size sample, even when d l MR . It is extracted as 36 :…”

Section: Provides Viamentioning

confidence: 99%

Sondheimer oscillations as a probe of non-ohmic flow in type-II Weyl semimetal WP2

Delft¹,

Wang²,

Putzke³

et al. 2021

Preprint

0

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As conductors in electronic applications shrink, microscopic conduction processes lead to strong deviations from Ohm’s law. Depending on the length scales of momentum conserving (lMC) and relaxing (lMR) electron scattering, and the device size (d), current flows may shift from ohmic to ballistic to hydrodynamic regimes and more exotic mixtures thereof. So far, an in situ, in-operando methodology to obtain these parameters self-consistently within a micro/nanodevice, and thereby identify its conduction regime, is critically lacking. In this context, we exploit Sondheimer oscillations, semi-classical magnetoresistance oscillations due to helical electronic motion, as a method to obtain lMR in micro-devices even when lMR>>d. This gives information on the bulk lMR complementary to quantum oscillations, which are sensitive to all scattering processes. We extract lMR from the Sondheimer amplitude in the topological semi-metal WP2, at elevated temperatures up to T~50 K, in a range most relevant for hydrodynamic transport phenomena. Our data on μm-sized devices are in excellent agreement with experimental reports of the large bulk lMR and thus confirm that WP2 can be microfabricated without degradation. Indeed, the measured scattering rates match well with those of theoretically predicted electron-phonon scattering, thus supporting the notion of strong momentum exchange between electrons and phonons in WP2 at these temperatures. These results conclusively establish Sondheimer oscillations as a quantitative probe of lMR in micro-devices in studying non-ohmic electron flow.

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