| Autor: |
Yuri, Zuev, Mun Seog, Kim, Thomas R, Lemberger |
| Rok vydání: |
2004 |
| Zdroj: |
Physical review letters. 95(13) |
| ISSN: |
0031-9007 |
| Popis: |
We report measurements of the ab-plane superfluid density n(s) (magnetic penetration depth lambda) of heavily underdoped films of YBa2Cu3O6+x, with T(C)'s from 6 to 50 K. We find the characteristic length for vortex unbinding transition equal to the film thickness, suggesting strongly coupled CuO2 layers. At the lowest dopings, T(C) is as much as 5 times larger than the upper limit set by the 2D Kosterlitz-Thouless-Berezinskii transition temperature calculated for individual CuO2 bilayers. Our main finding is that T(C) is not proportional to n(s)(0); instead, we find T(C) proportional to ns(1/2.3+/-0.4). This conflicts with a popular point of view that quasi-2D thermal phase fluctuations determine the transition temperature. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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