Pressure dependence of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">T</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="italic">c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>and charge transfer in<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></m

Almasan, C. C.; Han, Seung-Ho; Lee, B. W.; Paulius, L. M.; Maple, M. B.; Veal, B. W.; Downey, J.W.; Paulikas, A. P.; Fisk, Z.; Schirber, J. E.

doi:10.1103/physrevlett.69.680

Cited by 131 publications

(63 citation statements)

References 18 publications

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“…Therefore, it is natural to expect a nearly zero oxygen isotope effect in the optimally doped YBa 2 Cu 3 O 7Ϫ␦ for a BCS-type electron-phonon interaction pairing. It is worth noting that the doping dependence of ␣ in YBa 2 Cu 3 O 7Ϫ␦ resembles that of dlnT c /dP (36,37), signaling a nice correlation between the isotope and pressure effects.…”

Section: [3]mentioning

confidence: 99%

Unified picture of the oxygen isotope effect in cuprate superconductors

Chen

Struzhkin

et al. 2007

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

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High-temperature superconductivity in cuprates was discovered almost exactly 20 years ago, but a satisfactory theoretical explanation for this phenomenon is still lacking. The isotope effect has played an important role in establishing electron-phonon interaction as the dominant interaction in conventional superconductors. Here we present a unified picture of the oxygen isotope effect in cuprate superconductors based on a phonon-mediated d-wave pairing model within the Bardeen-Cooper-Schrieffer theory. We show that this model accounts for the magnitude of the isotope exponent as functions of the doping level as well as the variation between different cuprate superconductors. The isotope effect on the superconducting transition is also found to resemble the effect of pressure on the transition. These results indicate that the role of phonons should not be overlooked for explaining the superconductivity in cuprates.electron-phonon interaction ͉ high-temperature superconductivity ͉ pressure effect U nderstanding the high-temperature superconductivity in cuprate superconductors is at the heart of current research in solid-state physics. The isotope effect is an important experimental probe in revealing the underlying pairing mechanism of superconductivity. Early measurements (1) of the isotope effect on the superconducting transition temperature, T c , provided key experimental evidence for phonon-mediated pairing and supported strongly the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity in conventional materials. When hightemperature superconductivity was discovered in copper oxides, the oxygen isotope exponents, defined by ␣ ' ϪdlnT c /dlnM, with M being the isotopic mass, were promptly measured. The initial finding of the small value of ␣ in La 1.85 Sr 0.15 CuO 4 (2, 3) and near zero value in YBa 2 Cu 3 O 7Ϫ␦ (␦ ϳ 0) (4-6) was taken to be convincing evidence against electron-phonon interaction as the dominant mechanism in these materials. However, later experiments have revealed a much richer and more complex situation (7). There is a striking variation of ␣ with doping level in a given cuprate material (8-11). Meanwhile, ␣ also varies among various compounds of different cuprate families (7,12). Interestingly, ␣ is a remarkably monotonic function of the number of CuO 2 layers in a way opposite to T c in optimally doped compounds (12). Such elaborate isotope effects strongly suggest that one should include phonons in the theory of high-T c superconductivity. Studies of neutron scattering (13), angleresolved photoemission spectroscopy (14, 15), and scanning transmission electron microscopy (16) provide further evidence for phonons being an important player in the basic physics of high-T c superconductivity.Compared with isotope substitution, pressure has been realized not only to be another effective way to change T c for a superconductor (17) but also to yield information on the interaction causing the superconductivity. So far, the record high T c of 164 K was achieved under high pressure in HgBa 2 C...

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Section: [3]mentioning

confidence: 99%

Unified picture of the oxygen isotope effect in cuprate superconductors

Chen

Struzhkin

et al. 2007

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

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“…Murayama et al [21] showed from Hall coefficient measurements on Y124, Bi2212 and Tl221 that T c follows the T c (n h ) parabola via pressure induced doping, whereas for doped La214 a complete shift of the parabola to higher T c values and no pressure induced doping effect was found [44]. Almasan et al [35] and Iye [45] extended the simple charge transfer model assuming that the effect of pressure on T c consists of a change of the carrier density and an additional shift of the complete T c parabola to higher T c values expressed by dT c,max /dp. The influence of pressure on T c,max can easily be determined when T c,max is known at ambient pressure because in the maximum of the parabola the T c variation due to a pressure induced change of the hole concentration is zero.…”

Section: Introductionmentioning

confidence: 99%

“…A lot of experiments have been performed to determine dT c /dp of doped Y123 compounds [19,21,35,37,43,47,49,58,[64][65][66][67][68][69][70][71]. In the beginning of these investigations the results from different groups showed large scatter.…”

Section: Introductionmentioning

confidence: 99%

“…Several experiments on Y123 have shown that dT c /dp is nonlinear with decreasing oxygen content for 6.75<x<7.0 [35,61,69,71,81], although at least for oxygen contents from x=6.8 to 6.95 the change in the oxygen content should be nearly proportional to the n h change. In this range each added oxygen atom should be set to the end of a Cu-O-chain which is a consequence of oxygen ordering.…”

Section: Introductionmentioning

confidence: 99%

“…A lot of calculations based on experimental observations and theoretical models show that pressure dopes the CuO 2 planes from a charge reservoir. Data for the pressure induced charge transfer are given for example in [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. Murayama et al [21] showed from Hall coefficient measurements on Y124, Bi2212 and Tl221 that T c follows the T c (n h ) parabola via pressure induced doping, whereas for doped La214 a complete shift of the parabola to higher T c values and no pressure induced doping effect was found [44].…”

Section: Introductionmentioning

confidence: 99%

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The effect of chemical doping and hydrostatic pressure on Tc of Y1−yCayBa2Cu3Ox single crystals

Schlachter

Fietz²,

Grube³

et al. 1999

Physica C: Superconductivity

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We performed susceptibility measurements on Y 1-y Ca y Ba 2 Cu 3 O x single crystals under high He pressure. For each Ca content various samples with different oxygen contents have been prepared to probe the influence of Ca on T c (x), dT c /dp(x) and T c,max . Starting from the parabolic T c (n h ) behavior we calculated n h values from T c and T c,max for each sample. It is shown that in the overdoped region dT c /dp can be described by a pressure induced charge transfer with dn h /dp ≈ 3.7⋅10 -3 GPa -1 and a dT c,max /dp value of 0.8 K/GPa, irrespective of the Ca content. In the underdoped region additional pressure effects lead to a peak in dT c /dp at ≈0.11 holes/CuO 2 plane. However, with increasing Ca content this peak is strongly depressed. This is explained in terms of an increasing disorder in the CuO chain system due to doping. Deviations in dT c /dp at very low n h values can be assigned to the ortho II ordering in the CuO chain system.

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Empirical Rules for the Critical Temperature

Wesche¹

2015

Physical Properties of High‐Temperature Superconductors

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Pressure dependence ofTcand charge transfer inYBa2

Abstract: The superconducting critical temperature T c of YBa2Cu30 x single crystals (6.35^x^7) has been measured resistively as a function of pressure P (0 Show more

Cited by 131 publications

References 18 publications

Unified picture of the oxygen isotope effect in cuprate superconductors

Unified picture of the oxygen isotope effect in cuprate superconductors

The effect of chemical doping and hydrostatic pressure on Tc of Y1−yCayBa2Cu3Ox single crystals

Empirical Rules for the Critical Temperature

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