Magnetic-field penetration depth in TI2Ba2CuO6+δ in the overdoped regime

Uemura, Y. J.; Keren, Amit; Le, L. P.; Luke, G. M.; Wu, W. D.; Kubo, Yoshimi; Manako, T.; Shimakawa, Yuichi; Subramanian, M.A.; Cobb, Jonathan; Markert, J. T.

doi:10.1038/364605a0

Cited by 240 publications

(208 citation statements)

References 15 publications

Supporting

Mentioning

174

Contrasting

Order By: Relevance

“…Systems in the optimally doped region deviate from this linear line, showing a "plateau" like behavior, which was later found out to be due to the effect of the CuO chains in the case of the YBCO systems [29]. We see that the nearly linear trend is followed also by systems with Cu/Zn substitution [8], spontaneous formation of static magnetic regions (shown with the "stripe" symbols), and even with overdoping (Tl2201) [24], the implications of which will be discussed in later sections.…”

Section: Plots Of Tc Vs Ns/m * and Tc Vs Tfmentioning

confidence: 64%

“…As shown in Fig. 7(b), the "gapped" fraction, presumably representing the volume fraction of the superconducting region, closely follows the variation of the su-perfluid response n s /m * obtained from µSR [24].…”

Section: Phase Separation In the Overdoped Regionmentioning

confidence: 78%

“…1, n s /m * decreases with increasing carrier doping, yet conductivity studies imply no anomaly in m * . We presented a picture involving phase separation into superconducting and normal metal ground states [24,7], while authors of ref. [30] interpreted this in terms of pair-breaking scattering.…”

Section: Phase Separation In the Overdoped Regionmentioning

confidence: 99%

“…In 1993, our group [24] and a European µSR team [30] independently found a very strange variation of n s /m * in overdoped Tl2201. As shown in Fig.…”

Section: Phase Separation In the Overdoped Regionmentioning

confidence: 99%

See 3 more Smart Citations

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Uemura¹

2004

J. Phys.: Condens. Matter

123

View full text Add to dashboard Cite

To find out a primary determing factor of Tc and a pairing mechanism in high-Tc cuprates, we combine the muon spin relaxation results on ns/m * (superconducting carrier density / effective mass), accumulated over the last 15 years, with the results from neutron and Raman scattering, STM, specific heat, Nernst effect and ARPES measurements. We identify the neutron magnetic resonance mode as an analogue of roton minimum in the superfluid 4 He, and argue that ns/m * and the resonance mode energy ωres play a primary role in determining Tc in the underdoped region. We propose a picture that roton-like excitations in the cuprates appear as a coupled mode, which has the resonance mode for spin and charge responses at different momentum transfers but the same energy transfers, as detected respectively, by the neutron S=1 mode and the Raman S=0 A1g mode. We shall call this as the "hybrid spin/charge roton". After discussing the role of dimensionality in condensation, we propose a generic phase diagram of the cuprates with spatial phase separation in the overdoped region as a special case of the BE-BCS crossover conjecture where the superconducting coupling is lost rapidly in the overdoped region. Using a microscopic model of charge motion resonating with antiferomagnetic spin fluctuations, we propose a possibility that the hybrid spin/charge roton and higher-energy spin fluctuations mediate the superconducting pairing. In this model, the resonance modes can be viewed as a meson-analogue and the "dome" shape of the phase diagram can be understood as a natural consequence of departure from the competing Mott insulator ground state via carrier doping.

show abstract

Section: Plots Of Tc Vs Ns/m * and Tc Vs Tfmentioning

confidence: 64%

Section: Phase Separation In the Overdoped Regionmentioning

confidence: 78%

Section: Phase Separation In the Overdoped Regionmentioning

confidence: 99%

“…In 1993, our group [24] and a European µSR team [30] independently found a very strange variation of n s /m * in overdoped Tl2201. As shown in Fig.…”

Section: Phase Separation In the Overdoped Regionmentioning

confidence: 99%

See 2 more Smart Citations

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Uemura¹

2004

J. Phys.: Condens. Matter

123

View full text Add to dashboard Cite

show abstract

“…These models [3][4][5][6][7][8] assume the existence of pre-formed charge pairs above T c . Different pictures, however, assume single charge above T c based on the resonating-valence-bond concepts [9,10].Several anomalous results have been found also in the overdoped (OD) region: µSR studies on Tl 2 Ba 2 CuO 6+δ (Tl2201) [11,12] revealed that n s /m * at T → 0 decreases with increasing hole doping. This tendency has been observed subsequently in thin film La 2−x Sr x CuO 4 (LSCO) [13] and bulk YBa 2 Cu 3 O y (YBCO) [14] systems in the OD region.…”

mentioning

confidence: 99%

Microscopic phase separation in the overdoped region of high-Tc cuprate superconductors

Uemura

2001

Solid State Communications

View full text Add to dashboard Cite

We propose a phenomenological model for high-Tc superconductors (HTSC) assuming: (1) a microscopic phase separation between superconducting and normal-metal areas in the overdoped region; and (2) existence of a homogeneous superconducting phase only below the pseudo-gap T * line, which shows a sharp reduction towards T * ∼ 0 at a mildly overdoped critical concentration xc. This model explains anomalous doping and temperature dependences of ns/m * (superconducting carrier density / effective mass) observed in several overdoped HTSC systems. We point out an analogy to superfluid 4 He/ 3 He films, and discuss an energetic origin of microscopic phase separation. 74.25.Dw, Since the discovery of high-T c cuprate superconductors (HTSC), accumulated studies have revealed unusual phenomena in the underdoped (UD) region, such as, correlations between T c and n s /m * (superconducting carrier density / effective mass) at T → 0 shown by measurements of the magnetic field penetration depth λ [1], and the pseudo-gap phenomena [2]. These results stimulated development of various theories / models for condensation, including Bose-Einstein (BE) to BCS crossover [3,4], phase fluctuations [5,6], XY-model [7] and BE condensation [8]. These models [3][4][5][6][7][8] assume the existence of pre-formed charge pairs above T c . Different pictures, however, assume single charge above T c based on the resonating-valence-bond concepts [9,10].Several anomalous results have been found also in the overdoped (OD) region: µSR studies on Tl 2 Ba 2 CuO 6+δ (Tl2201) [11,12] revealed that n s /m * at T → 0 decreases with increasing hole doping. This tendency has been observed subsequently in thin film La 2−x Sr x CuO 4 (LSCO) [13] and bulk YBa 2 Cu 3 O y (YBCO) [14] systems in the OD region. The "coherence peak" in ARPES spectra [15] also follows this behavior of n s /m * in the OD region. Meanwhile, Tallon and Loram [16] noticed a sharp reduction of the pseudo-gap T * line in the temperature T vs. hole-concentration x phase diagram heading towards T * ∼ 0 at a critical concentration x c ∼ 0.19 holes/Cu which lies in the mildly OD region. In view of the existence of superconductivity in x > x c where the T * line does not exist, Tallon and Loram [16] have advocated a view point that the pseudogap phenomena is not representing pre-cursor superconducting phenomena, but should be ascribed to a tendency towards a ground state competing with superconductivity.We have, however, suggested another possible view point in which T * is ascribed to a signature of a gradual pre-formation of pairs [4] while the anomaly in the OD region to a phase separation [4,11,17,18]. In the present paper, resorting to a model-calculation of n s /m * , comparison with experimental results, a crude estimate of competing electrostatic and condensation/pairing energies, and analogy to 4 He/ 3 He films, we demonstrate that our picture with microscopic phase separation between superconducting and normal-metal regions can quantitatively account for several anomalous results in ...

show abstract

Magnetic Penetration Depths in Cuprates: A short Review of Measurement Techniques and Results

Hardy

Kamal

Bonn

NATO Science Series: B:

View full text Add to dashboard Cite

Magnetic-field penetration depth in TI2Ba2CuO6+δ in the overdoped regime

Cited by 240 publications

References 15 publications

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Microscopic phase separation in the overdoped region of high-Tc cuprate superconductors

Magnetic Penetration Depths in Cuprates: A short Review of Measurement Techniques and Results

Contact Info

Product

Resources

About

Magnetic-field penetration depth in TI2Ba2CuO6+δ in the overdoped regime

Cited by 240 publications

References 15 publications

Condensation, excitation, pairing, and superfluid density in high-Tc superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Condensation, excitation, pairing, and superfluid density in high-Tc superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Microscopic phase separation in the overdoped region of high-Tc cuprate superconductors

Magnetic Penetration Depths in Cuprates: A short Review of Measurement Techniques and Results

Contact Info

Product

Resources

About

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing