Evidence for strong electron-phonon coupling from the specific heat of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">YBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mr

Reeves, M. E.; Ditmars, David A.; Wolf, Stuart A.; Vanderah, Terrell A.; Kresin, Vladimir Z.

doi:10.1103/physrevb.47.6065

Cited by 34 publications

(17 citation statements)

References 26 publications

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“…37͒ are also consistent with electronic specific-heat coefficients for Y124 and Y123 obtained by Junod et al 12 and Willis et al 11 The mass enhancement factor for Y124 is unknown but a value can be estimated from the W ϱ values for Y124 and Y123 ͑Fig. 3͒, the average of the electronic specific-heat coefficients 11,12,37 and the ⌳ estimates for Y123. 37,38 Assuming ⌳ 123 is about 2.5, 37,38 one obtains ⌳ 124 Ϸ1.7.…”

Section: Discussionsupporting

confidence: 87%

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Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
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The thermal conductivity and electrical resistivity were measured on two samples of the cuprate superconductor YBa 2 Cu 4 O 8 ͑Y124͒. The results pass through a maximum at about half of the superconducting transition temperature T c . The peak value is much higher than the peak value for polycrystalline YBa 2 Cu 3 O 7Ϫ␦ , Y123, and is about equal to ab plane values for good melt processed Y123. In the normal state most of the is due to phonon transport p and estimates of p were obtained from the data by making a correction for electronic transport. Phonon-phonon and phonon-electron scattering limit the p of both Y124 and Y123. In the two compounds, the phonon-phonon scattering is about equally strong, but electron-phonon scattering is considerably weaker in Y124. In the superconducting state, below the maximum at T c /2, varies as T n (nϷ1/2). This behavior has also been observed in Y123, but is not consistent with phonon scattering theory. The implications of this observation are discussed. ͓S0163-1829͑98͒08117-X͔ THERMAL CONDUCTIVITY OF POLYCRYSTALLINE . . .

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Section: Discussionsupporting

confidence: 87%

“…3͒, the average of the electronic specific-heat coefficients 11,12,37 and the ⌳ estimates for Y123. 37,38 Assuming ⌳ 123 is about 2.5, 37,38 one obtains ⌳ 124 Ϸ1.7.…”

Section: Discussionmentioning

confidence: 99%

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
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“…Within a quasiparticle interpretation, κe (L0) κ, and therefore, we would conclude that the high-temperature thermal transport is dominated by phonons. Even without assuming quasiparticles, at high temperature, the phonon specific heat is overwhelmingly large compared with that of the electrons (23,52). Thus, because the product of the specific heat and our measured diffusivity yields the commonly measured thermal conductivity, the naive conclusion is that phonons dominate the high-temperature thermal transport, and we should expect to measure κ = cD ≈ c ph D ph = κ ph .…”

Section: Significancementioning

confidence: 99%

Anomalous thermal diffusivity in underdoped YBa ₂ Cu ₃ O _6+x

Zhang

Levenson-Falk

Ramshaw

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The thermal diffusivity in the ab plane of underdoped YBCO crystals is measured by means of a local optical technique in the temperature range of 25-300 K. The phase delay between a point heat source and a set of detection points around it allows for high-resolution measurement of the thermal diffusivity and its in-plane anisotropy. Although the magnitude of the diffusivity may suggest that it originates from phonons, its anisotropy is comparable with reported values of the electrical resistivity anisotropy. Furthermore, the anisotropy drops sharply below the charge order transition, again similar to the electrical resistivity anisotropy. Both of these observations suggest that the thermal diffusivity has pronounced electronic as well as phononic character. At the same time, the small electrical and thermal conductivities at high temperatures imply that neither well-defined electron nor phonon quasiparticles are present in this material. We interpret our results through a strongly interacting incoherent electron-phonon "soup" picture characterized by a diffusion constant D ∼ v 2 B τ , where v B is the soup velocity, and scattering of both electrons and phonons saturates a quantum thermal relaxation time τ ∼ /k B T.thermal diffusivity | bad metals | electron-phonon T he standard paradigm for transport in metals relies on the existence of quasiparticles. Electronic quasiparticles conduct electricity and heat. Phonon quasiparticles, the collective excitations of the elastic solid (here, we discuss acoustic phonons) also conduct heat. Transport coefficients, such as electrical and thermal conductivities, can then be calculated using, for example, Boltzmann equations (1). However, such an approach fails when the quasiparticle mean free paths become comparable with the quasiparticle wavelength. For electrons, it is the Fermi wavelength (2-4), whereas for phonons, it is the larger of the interatomic distance or minimum excited phonon wavelength (5, 6). Understanding transport in nonquasiparticle regimes requires a new framework and has become a subject of intense theoretical effort in recent years, triggering an urgent need for experimental results that can shed light on such regimes. In particular, in ref. 7, the diffusivity was singled out as a key observable for incoherent nonquasiparticle transport, possibly subject to fundamental quantum mechanical bounds.In this work, we report high-resolution measurements of the thermal diffusivity of single-crystal underdoped YBCO6.60 (an ortho-II YBa2Cu3O6.60) and YBCO6.75 (an ortho-III YBa2Cu3O6.75). We are particularly interested in the anisotropy of the thermal diffusivity as measured along the principal axes a and b (which is the chain direction) in the temperature range 25-300 K. We use a noncontact optical microscope (see Fig. S1) to perform local thermal transport measurements on the scale of ∼10 µm, hence avoiding inhomogeneities, particularly twinning and grain boundary effects. Our principal experimental results are as follows. (i) The measured thermal diffusivity is...

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“…Further, the critical fields needed to suppress superconductivity are much higher (hundreds of tesla) than achievable in present day laboratory magnets. Thus, only a few groups have attempted to extract the electronic specific heat [5][6][7][8] over a wide temperature range, and most of the experimental effort has gone into characterizing superconducting anomaly at T c (for a recent review, see ref. 3).…”

Section: Introductionmentioning

confidence: 99%

“…7) Subsequently, Loram et al 5) made highprecision measurements of the specific heat of YBa 2 Cu 3 O x measurements up to 250 K using a differential method, in which non-superconducting Zn-doped YBa 2 Cu 3 O x was used as a reference material. Evidence for a pseudogap in the normal state electronic excitations was found from this analysis.…”

Section: Introductionmentioning

confidence: 99%

Specific-Heat of YBa₂Cu₃O_xup to 400 K: High-Resolution Adiabatic Measurements andAb-initioLDA Phonon Calculations

et al. 2009

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The specific heat of YBa 2 Cu 3 O x (x ¼ 6:7, 6.9, and 7.0) has been determined to within 0.1% accuracy from 5 to 400 K using adiabatic calorimetry. The phonon specific heat contribution for x ¼ 7:0 is calculated using ab-initio LDA and subtracted from the experimental data, yielding estimates of the oxygen-ordering and electronic heat capacity contributions. The oxygen-ordering contribution agrees well with theoretical predictions. Although the LDA phonon heat capacity is found to be very accurate, it is not quite precise enough to reliably determine the electronic term over the whole temperature range. We demonstrate how small changes in the phonon density of states can affect the results, which underlines the extreme difficulty in accurately determining the electronic heat capacity of YBa 2 Cu 3 O x .

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Evidence for strong electron-phonon coupling from the specific heat ofYBa2Cu3

Cited by 34 publications

References 26 publications

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
View full text Add to dashboard Cite

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
View full text Add to dashboard Cite

Anomalous thermal diffusivity in underdoped YBa ₂ Cu ₃ O _6+x

Specific-Heat of YBa₂Cu₃O_xup to 400 K: High-Resolution Adiabatic Measurements andAb-initioLDA Phonon Calculations

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Evidence for strong electron-phonon coupling from the specific heat ofYBa2Cu3

Cited by 34 publications

References 26 publications

Thermal conductivity of polycrystallineYBa2Cu4O8Williams1, Scarbrough2, Schmitz3 et al. 1998Phys. Rev. B10050View full textAdd to dashboardCite

Thermal conductivity of polycrystallineYBa2Cu4O8Williams1, Scarbrough2, Schmitz3 et al. 1998Phys. Rev. B10050View full textAdd to dashboardCite

Anomalous thermal diffusivity in underdoped YBa 2 Cu 3 O 6+x

Specific-Heat of YBa2Cu3Oxup to 400 K: High-Resolution Adiabatic Measurements andAb-initioLDA Phonon Calculations

Contact Info

Product

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About

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
View full text Add to dashboard Cite

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
View full text Add to dashboard Cite

Anomalous thermal diffusivity in underdoped YBa ₂ Cu ₃ O _6+x

Specific-Heat of YBa₂Cu₃O_xup to 400 K: High-Resolution Adiabatic Measurements andAb-initioLDA Phonon Calculations