Far-infraredc-axis response ofLa1.87Sr

Abstract

Far-infrared c-axis response of (La, Sr)2CuO4-delta determined by ellipsometry Henn, R.; Kircher, J.; Cardona, M.; Wittlin, A.; Duijn, V.H.M.; Menovsky, A.A. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible.

Dynamics of thec-polarized infrared-active modes in La2−xSrx

“…2͒ we observe in total four phonon modes. We note that, contrary to our earlier reports, 10,19 for the Sr doped samples we do not observe a splitting of the strongest mode at 235 cm Ϫ1 . We attribute this difference to a lower quality of the crystal used in the previous work.…”

“…1͒, it has been concluded that they arise from the Brillouin zone folding produced by the orthorhombic distortion of the crystal. 10,19 Consistent with the small orthorhombic distortion, both modes have a small oscillator strength. The two stronger modes at 235 cm Ϫ1 and 500 cm Ϫ1 are already present in the tetragonal high-temperature phase and represent two of the three expected c-polarized, infrared-active A 2u modes for the tetragonal phase ͑for the orthorhombic phase six infrared-active modes having c polarization, corre- sponding to B 1u symmetry, are predicted based on symmetry considerations͒.…”

Evidence of coherentc-axis charge transport in underdopedLa2−xSrxCuOKim1, Hor2, Dong3 et al. 2005Phys. Rev. B9001View full textAdd to dashboardCite

“…[8][9][10][11][12] It is found that only in the superconducting state does there develop a plasma edgelike structure out of the otherwise insulatorlike normal state c-axis reflectivity.…”

Optical absorptivity ofLa1.87Sr0.13CuO4Birmingham1, Grannan2, Richards3 et al. 1999Phys. Rev. BSelf Cite2000View full textAdd to dashboardCite

“…While there is no disagreement about the position of the peaks, 13 the interpretation of the continuum between them remains in dispute. Kim et al point 11 to signatures of incoherent transport above T c , i.e., a Drude liquid with an extremely high scattering rate and plasma frequency ͑''dirty'' limit parametrization.͒ However, Tamasaku et al, 2 and later Henn et al, 12 interpret very similar data using a Drude model with a small scattering rate and plasma frequency ͑pa-rametrization approaching the ''clean'' limit.͒ Below T c the optical response is dominated by the plasma edge. The c-axis absorptivity in 214 materials is much larger than the in-plane absorptivity, and hence the plasma edge dominated the loss seen in the early investigations using the polycrystalline samples.…”

“…[5][6][7][8][9] More recently, single crystals have become available, and the c-axis optical response has been measured separately from the in-plane optical response. 2,10,11,12 Above T c , the far-infrared reflectivity along the c axis is typical of a doped insulator, with strong phonon peaks seen on top of an electronic background. While there is no disagreement about the position of the peaks, 13 the interpretation of the continuum between them remains in dispute.…”