Heat capacity of superconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>1.85</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">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>0.15</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml

Dunlap, B. D.; Nevitt, M. V.; Ślaski, M.; Klippert, T. E.; Sungaila, Z.; McKale, A. G.; Capone, D. W.; Poeppel, R.B.; Flandermeyer, B. K.

doi:10.1103/physrevb.35.7210

Cited by 66 publications

(4 citation statements)

References 17 publications

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“…However, the situation changes markedly if the impurity contribution dominates the BCS-type contribution and the contribution of bosonic Cooper pairs to C e (T ). In this case the jumps of C e (T ) above T c will be largely modified (i.e., strongly depressed) by the relatively large impurity contribution to the C e (T ) and become less pronounced BCS-type anomalies, as observed in experiments [33,174]. Theoretical results obtained for C e (T ≤ T * ), which are compared with the experimental data on the electronic specific heat reported by Oda's group for LSCO, are presented in Fig.…”

Section: F Specific Heat Anomalies Of High-tc Cuprates In the Normal ...mentioning

confidence: 82%

“…[166]) in YBCO might be a BCS-type anomaly of C e (T ) around T * 220K. Dunlap et al [174] also reported the existence of a phase transition in LSCO at T * ≈ 80K, which is probably associated with a BCS-type transition at the pseudogap formation temperature. While Loram et al argued [167] that there is no such a phase transition in the normal state of high-T c cuprates.…”

Section: F Specific Heat Anomalies Of High-tc Cuprates In the Normal ...mentioning

confidence: 95%

“…The existing experimental facts concerning the high-T c cuprate superconductors [33,59,60,166,172,174,229,230,237] indicate that the electronic specific heat C e in these materials is proportional to T 2 or T 3 at low temperatures and has a clear λ-like anomaly at T c and a second anomaly somewhat below T c or well below T c . We believe that the electronic specific heat of high-T c cuprates below T c is best described by the theory of a superfluid Bose-liquid (see Eq.…”

Section: Integer and Half-integer Magnetic Flux Quantization Effectsmentioning

confidence: 99%

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Microscopic theory of pseudogap phenomena and unconventional Bose-liquid superconductivity and superfluidity in high-$T_c$ cuprates and other systems

Dzhumanov

2019

Preprint

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In this work, the consistent, predictive and empirically adequate microscopic theory of pseudogap phenomena and unconventional Bose-liquid superconductivity (superfluidity) is presented, based on the fact that in high-Tc cuprates and other related systems the energy εA of the effective attraction between fermionic quasiparticles is comparable with their Fermi energy εF and the bosonic Cooper pairs are formed above Tc (the temperature of the superfluid transition) and then a small part of such Cooper pairs condense into a Bose superfluid at Tc. According to this theory, the doped high-Tc cuprates and other systems with low Fermi energies (εF ∼ εA) are unconventional bosonic superconductors/superfluids and exhibit pseudogap phases above Tc, λ-like superconducting transition at Tc and Bose-liquid superconductivity below Tc. The relevant charge carriers in high-Tc cuprates are polarons which are bound into bosonic Cooper pairs above Tc. Polaronic effects and related pseudogap weaken with increasing the doping and disappear at a quantum critical point where a small Fermi surface of polarons transforms into a large Fermi surface of quasi-free carriers. The modified BCS-like theory describes another pseudogap regime but the superconducting/superfluid transition in high-Tc cuprates and related systems is neither the BCS-like transition nor the usual Bose-Einstein condensation. A good quantitative agreement is found between pseudogap theory and experiment. Universal criteria for bosonization of Cooper pairs are formulated in terms of two fundamental ratios εA/εF and ∆F /εF (where ∆F is the BCS-like gap). The mean-field theory of the coherent single particle and pair condensates of bosonic Cooper pairs describes fairly well the novel superconducting states (i.e., two distinct superconducting A and B phases below Tc and a vortexlike state above Tc) and various salient features (λ-like transition at Tc, kink-like anomalies in all superconducting/superfluid parameters near the first-order phase transition temperature T * c lower than Tc, gapless excitations below T * c and two-peak specific heat anomalies) of high-Tc cuprates in full agreement with the experimental findings. Though Bose-liquid superconductivity in the bulk of high-Tc cuprates is destroyed at Tc, but it can persist above Tc at grain boundaries and interfaces of these materials up to room temperature. The unusual superconducting/superfluid states and properties of other exotic systems (e.g., heavy-fermion and organic compounds, Sr2RuO4, 3 He, 4 He and atomic Fermi gases) are explained more clearly by the theory of Bose superfluids. Finally, the new criteria and principles of unconventional superconductivity and superfluidity are formulated.

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Section: F Specific Heat Anomalies Of High-tc Cuprates In the Normal ...mentioning

confidence: 82%

Section: F Specific Heat Anomalies Of High-tc Cuprates In the Normal ...mentioning

confidence: 95%

Section: Integer and Half-integer Magnetic Flux Quantization Effectsmentioning

confidence: 99%

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Microscopic theory of pseudogap phenomena and unconventional Bose-liquid superconductivity and superfluidity in high-$T_c$ cuprates and other systems

Dzhumanov

2019

Preprint

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“…Therefore, the critical problem must be solved by precise calorimetry, as the heat capacity provides the bulk property. The heat capacity anomaly due to superconducting phase transition was observed in La-M-Cu-O compounds (M = Ca, Ba, and Sr) [69][70][71][72][73][74][75][76], and thus the bulk superconductivity has been confirmed. The higher T c compound, YBa 2 Cu 3 O 7Àd , was found in 1987 [77][78][79], and the heat capacity measurements [80,81] showed the heat capacity jump at the superconducting phase transition, which gave a key information about the mechanism of the superconductivity.…”

Section: Critical Problems Solved By Calorimetry and Thermodynamicsmentioning

confidence: 94%

Application of calorimetry and thermodynamics to critical problems in materials science

Ataké¹

2009

The Journal of Chemical Thermodynamics

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Theory of High‐Temperature Superconductivity

Chen

Lü

1991

Physica Status Solidi (b)

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A new mechanism for the high-T, superconductivity is suggested. The antiferromagnetic order of the Cu spins between two neighbour 0 holes, i.e. the localized antiferromagnetic correlation may be the origin giving rise to the hole pair. The maximum of T, is calculated for the Y-Ba-Cu-0 superconductor using the similar method of calculating the antiferromagnet Nee1 temperature. The conclusion is made that the maximum of T, for the Y-Ba-Cu-0 superconductor is between 107.9 and 155.2K, and the energy gap 24(0) = 3.54kBT,. Many theories have been given to account for the high transition temperature of the oxide superconductors, most of them being based on pairing. Some are related to the origin of the strong antiferromagnetic correlation that gives rise to the hole pairs. The corresponding mechanisms reported include the resonating valence bond state [6], the antiferromagnetic spin fluctuations [l, 71, and the hole coupling with localized spins [8,9]. In this paper we suggest that the direct, strong antiferromagnetic correlation in the Cu-0 sheet gives rise to the hole pairs. In our model, the holes are on 0 sites and on Cu sites as well in the C u -0 sheet and move by 0 -C u -0 hopping. We consider that the lifetime of a hole on an 0 site is ') Chanchun 130023, People's Republic of China.

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Heat capacity of superconductingLa1.85Sr0.15

Cited by 66 publications

References 17 publications

Microscopic theory of pseudogap phenomena and unconventional Bose-liquid superconductivity and superfluidity in high-$T_c$ cuprates and other systems

Microscopic theory of pseudogap phenomena and unconventional Bose-liquid superconductivity and superfluidity in high-$T_c$ cuprates and other systems

Application of calorimetry and thermodynamics to critical problems in materials science

Theory of High‐Temperature Superconductivity

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