Development of high frequency and wide bandwidth Johnson noise thermometry

Crossno, Jesse; Liu, Xiaomeng; Ohki, Thomas A.; Kim, Philip; Fong, Kin Chung

doi:10.1063/1.4905926

Cited by 37 publications

(37 citation statements)

References 34 publications

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“…3c), such as "supercollisions" [62]: a three-body collision between an electron, phonon and impurity that leads to ρ ∼ T 3 scaling. Heat transfer measurements also confirm the importance of the substrate as a source of optical phonons which strongly couple to the electrons in graphene at higher temperatures [63].…”

Section: Phononsmentioning

confidence: 68%

Hydrodynamics of electrons in graphene

Lucas

Fong

2018

J. Phys.: Condens. Matter

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370

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Generic interacting many-body quantum systems are believed to behave as classical fluids on long time and length scales. Due to rapid progress in growing exceptionally pure crystals, we are now able to experimentally observe this collective motion of electrons in solid-state systems, including graphene. We present a review of recent progress in understanding the hydrodynamic limit of electronic motion in graphene, written for physicists from diverse communities. We begin by discussing the "phase diagram" of graphene, and the inevitable presence of impurities and phonons in experimental systems. We derive hydrodynamics, both from a phenomenological perspective and using kinetic theory. We then describe how hydrodynamic electron flow is visible in electronic transport measurements. Although we focus on graphene in this review, the broader framework naturally generalizes to other materials. We assume only basic knowledge of condensed matter physics, and no prior knowledge of hydrodynamics.

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Section: Phononsmentioning

confidence: 68%

Hydrodynamics of electrons in graphene

Lucas

Fong

2018

J. Phys.: Condens. Matter

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370

451

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“…Johnson noise thermometry (JNT) relies on measuring the total noise power emitted in a specified frequency band and relating that to the electronic temperature on the device; to maximize the sensitivity, high frequency and wide bandwidth measurements should be made [33]. In the temperature range discussed here, the upper frequency limit for JNT is typically set by the amount of stray capacitance from the graphene, lead wires, and contact pads to the Si back gate.…”

Section: Optimizing Samples For High Frequency Thermal Conductivity Mmentioning

confidence: 99%

“…The full Johnson noise thermometry (JNT) setup used in this study is outlined in detail in [33]. Here, we only give a brief synopsis for completeness.…”

Section: Johnson Noise Thermometrymentioning

confidence: 99%

“…As temperature increases, electron-phonon scattering becomes appreciable and thermal transport becomes limited by the electronphonon coupling strength [34][35][36]. The onset temperature of appreciable electron-phonon scattering, T el−ph , depends on the sample disorder and device geometry: T el−ph ∼80 K [33,34,37,38] for our samples. Below this temperature, the electronic contribution of the thermal conductivity can be obtained from P and ∆T using the device dimensions (SM).…”

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confidence: 99%

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Observation of the Dirac fluid and the breakdown of the Wiedemann-Franz law in graphene

Crossno

Shi

Wang

et al. 2016

Science

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666

702

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Interactions between particles in quantum many-body systems can lead to collective behavior described by hydrodynamics. One such system is the electron-hole plasma in graphene near the charge-neutrality point, which can form a strongly coupled Dirac fluid. This charge-neutral plasma of quasi-relativistic fermions is expected to exhibit a substantial enhancement of the thermal conductivity, thanks to decoupling of charge and heat currents within hydrodynamics. Employing high-sensitivity Johnson noise thermometry, we report an order of magnitude increase in the thermal conductivity and the breakdown of the Wiedemann-Franz law in the thermally populated charge-neutral plasma in graphene. This result is a signature of the Dirac fluid and constitutes direct evidence of collective motion in a quantum electronic fluid.

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“…5 we show the effects of the density of impurities on κ e , considering different residual electrical resistivities (1/σ imp ) and the validity of Wiedemann-Franz law for the electronic contributions to the electrical and thermal conductivities limited by impurity scatterings [19][20][21], for 1/σ imp in a range between 0 and a maximum of 40 Ω that has been reported in Ref. [9] (1/σ imp largely depends on the sample condition, doping method, and the substrate).…”

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confidence: 99%

The Electronic Thermal Conductivity of Graphene

2016

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Graphene, as a semimetal with the largest known thermal conductivity, is an ideal system to study the interplay between electronic and lattice contributions to thermal transport. While the total electrical and thermal conductivity have been extensively investigated, a detailed first-principles study of its electronic thermal conductivity is still missing. Here, we first characterize the electron-phonon intrinsic contribution to the electronic thermal resistivity of graphene as a function of doping using electronic and phonon dispersions and electron-phonon couplings calculated from first principles at the level of density-functional theory and many-body perturbation theory (GW). Then, we include extrinsic electron-impurity scattering using low-temperature experimental estimates. Under these conditions, we find that the in-plane electronic thermal conductivity κe of doped graphene is ∼300 W/mK at room temperature, independently of doping. This result is much larger than expected, and comparable to the total thermal conductivity of typical metals, contributing ∼10 % to the total thermal conductivity of bulk graphene. Notably, in samples whose physical or domain sizes are of the order of few micrometers or smaller, the relative contribution coming from the electronic thermal conductivity is more important than in the bulk limit, since lattice thermal conductivity is much more sensitive to sample or grain size at these scales. Last, when electron-impurity scattering effects are included, we find that the electronic thermal conductivity is reduced by 30 to 70 %. We also find that the Wiedemann-Franz law is broadly satisfied at low and high temperatures, but with the largest deviations of 20-50 % around room temperature.The thermal conductivity of graphene is extremely high, which is not only fascinating from the scientific point of view, but is also promising for many technological applications. So far, a fairly wide range of thermal conductivities have been reported experimentally [1][2][3][4], with the measured thermal conductivity of suspended graphene at room temperature ranging from 2600 to 5300 W/mK [1, 2], which is higher than that of any other known material. The measured thermal conductivity of graphene supported on a substrate is much lower (370-600 W/mK) than that of the suspended case, but still comparable to or higher than that of typical metals [3,4]. It is widely assumed that most of the thermal conduction is carried by phonons [5] and that the electronic contribution is negligible, with experiments hinting that the electronic thermal conductivity κ e obtained from the measured electrical conductivity by applying the Wiedemann-Franz law could be as low as 1 % of the total thermal conductivity [6].In typical metals, the total thermal conductivity is the sum of the electronic contribution κ e and the phonon contribution κ ph . The kinetic theory of electrons and phonons provides a qualitative description of the temperature dependence of κ e and κ ph in the low-and hightemperature limits. The electronic t...

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Development of high frequency and wide bandwidth Johnson noise thermometry

Cited by 37 publications

References 34 publications

Hydrodynamics of electrons in graphene

Hydrodynamics of electrons in graphene

Observation of the Dirac fluid and the breakdown of the Wiedemann-Franz law in graphene

The Electronic Thermal Conductivity of Graphene

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