Persistence of Strong Electron Coupling to a Narrow Boson Spectrum in Overdoped Bi2Sr2CaCu2O8+δ Tunneling Data
Abstract
A d-wave, Eliashberg analysis of break-junction and STM tunneling spectra on Bi2Sr2CaCu2O8+δ (Bi2212) reveals that the spectral dip feature is directly linked to strong electronic coupling to a narrow boson spectrum, evidenced by a large peak in α2F(ω). The tunneling dip feature remains robust in the overdoped regime of Bi2212 with bulk Tc values of 56 K-62 K. This is contrary to recent optical conductivity measurements of the self-energy that suggest the narrow boson spectrum disappears in overdoped Bi2212 and therefore cannot be essential for the pairing mechanism. The discrepancy is resolved by considering the way each technique probes the electron self-energy, in particular, the unique sensitivity of tunneling to the off-diagonal or pairing part of the self-energy.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 2006
- DOI:
- 10.1103/PhysRevLett.96.017004
- arXiv:
- arXiv:cond-mat/0510057
- Bibcode:
- 2006PhRvL..96a7004Z
- Keywords:
-
- 74.50.+r;
- 73.40.Gk;
- 74.45.+c;
- Tunneling phenomena;
- point contacts weak links Josephson effects;
- Tunneling;
- Proximity effects;
- Andreev effect;
- SN and SNS junctions;
- Condensed Matter - Superconductivity;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- RevTex4. 5 pages. 3 figures. Submitted to Physical Review Letters