Münster 1997 – scientific programme
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TT: Tiefe Temperaturen
TT 19: Postersitzung III: Josephsonkontakte(1-25), SQUIDs, Sensoren, Detektoren(26-37), Supraleitung in Hochfrequenz und Elektronik(38-45), Präparation und Dotierung von HTSL(46-53), NMR und Ultraschall in HTSL(54-60), Thermodynamik, Magnetismus(61-68), Transporteigenschaften von HTSL(69-73), Spektroskopie, Ramanstreuung, param. Meissner-Effekt in HTSL(74-84), n-dotierte HTSL(85-91)
TT 19.77: Poster
Thursday, March 20, 1997, 15:30–19:00, Z1
Electronic Raman scattering in Tl2Ba2CuO6+δ: oxygen doping and resonance effects — •L.V. Gasparov1,2, P. Lemmens1, N.N. Kolesnikov2, and G. G"untherodt1 — 12. Physikalisches Institut, Rheinisch-Westf"alische Technische Hochschule Aachen, Templergraben 55, D-52056 Aachen — 2Institute for Solid State Physics, Chernogolovka, Moscow district, 142432, Russia
Single crystals of the optimallydoped and overdoped
Tl2Ba2CuO6+δ (Tl-2201) with Tc=86 and 30K, respectively,
have been investigated by polarized Raman scattering. The superconducting
transition manifests itself as a redistribution of the Raman intensity
forming a broad, symmetry-dependent peak at temperatures below Tc.
For the optimally doped Tl-2201 the peaks for the A1g and B1g
scattering componens are found at ≈350cm−1 and
≈430cm−1, respectively.
While tuning the incident photon energy from 2.42 to 2.62 eV the lineshape of
the A1g peak changes providing experimental evidence for the importance
of resonance effects in the electronic Raman scattering of Tl-2201. In the
overdoped Tl-2201 the peaks of the A1g, B1g and B2g
scattering components are found at 40, 55 and 55cm−1, respectively.
In contrast to the optimally doped Tl-2201
(2Δmax/kB Tc ≈7.4, assuming d-wave pairing) in overdoped
Tl-2201 we obtain 2Δmax/kB Tc ≈ 3 close to the typical
BCS value.
- Work supported by DFG/SFB 341 and BMBF 13 FKZ N6586. - L.V.G acknowledges
support from the Alexander von Humboldt Foundation.