Temperature evolution of the pseudogap state in the infrared response of underdoped La 2 2 x Sr x CuO
نویسندگان
چکیده
The ab-plane optical spectra of two single crystals of underdoped La22xSrxCuO4 were investigated. The reflectivity of La1.87Sr0.13CuO4 has been measured in the frequency range 30– 9000 cm 21 ~0.004–1 eV! both parallel and perpendicular to the CuO2 planes, whereas La1.86Sr0.14CuO4 was studied only in the ab plane. The extended Drude model shows that the frequency-dependent effective scattering rate 1/t(v ,T) is strongly suppressed below the high-frequency straight-line extrapolation, a signature of the pseudogap state. This suppression can be seen from temperatures below the superconducting transition up to 400 K. In the case of underdoped LSCO the straight-line extrapolation is temperature independent below 200 K, whereas above 200 K there is a strong temperature dependence of the high-frequency 1/t(v ,T). The out-of-plane direction is also examined for evidence of the pseudogap state. @S0163-1829~99!08009-1#
منابع مشابه
Correlations versus Superfluid Density in La 2 − x Sr x CuO
We have performed muon spin relaxation and low field ac-susceptibility measurements in a series of high quality samples of La 2−x Sr x CuO 4 (x = 0.08 − 0.24) as a function of temperature. Superconductivity is found to co-exist with low temperature spin glass order up to the optimally doped region where the normal state pseudogap also closes. The systematic depletion of the superfluid density w...
متن کاملThe Meissner effect in a strongly underdoped cuprate above its critical temperature
The Meissner effect and associated perfect 'bulk' diamagnetism together with zero resistance and gap opening are characteristic features of the superconducting state. In the pseudogap state of cuprates, unusual diamagnetic signals and anomalous proximity effects have been detected, but a Meissner effect has never been observed. Here we probe the local diamagnetic response in the normal state of...
متن کاملIncommensurate magnetic order and dynamics induced by spinless impurities in YBa(2)Cu(3)O(6.6).
We report an inelastic-neutron-scattering and muon-spin-relaxation study of the effect of 2% spinless (Zn) impurities on the magnetic order and dynamics of YBa(2)Cu(3)O(6.6), an underdoped high-temperature superconductor that exhibits a prominent spin pseudogap in its normal state. Zn substitution induces static magnetic order at low temperatures and triggers a large-scale spectral-weight redis...
متن کاملOptical Properties of (pr,ce) 2 Cuo 4
We studied the optical conductivity of electron doped Pr1−xCexCuO4 from the underdoped to the overdoped regime. The observation of low to high frequency spectral weight transfer reveals the presence of a gap, except in the overdoped regime. A Drude peak at all temperatures shows the partial nature of this gap. The close proximity of the doping at which the gap vanishes to the antiferro-magnetic...
متن کاملNeutron-scattering evidence for a periodically modulated superconducting phase in the underdoped cuprate La1.905Ba0.095CuO4.
The role of antiferromagnetic spin correlations in high-temperature superconductors remains a matter of debate. We present inelastic neutron-scattering evidence that gapless spin fluctuations coexist with superconductivity in La1.905Ba0.095CuO4. Furthermore, we observe that both the low-energy magnetic spectral weight and the spin incommensurability are enhanced with the onset of superconductin...
متن کامل