CRITICAL FLUCTUATIONS AND LOWEST-LANDAU-LEVEL SCALING OF THE SPECIFIC-HEAT OF HIGH-TEMPERATURE SUPERCONDUCTORS

The specific heat data of various high-temperature superconducting mat erials at finite magnetic field and temperatures near the transition t emperature are studied. It is found that lowest-landau-level (LLL) sca ling is a good description of the data for fields larger than a charac teristic field Hsimilar to 0(1 T) and that it breaks down for fields less than H. The scaled data agrees very well with the calculated sca ling functions, which provides further evidence for the validity of LL L theory at fields H greater than or equal to H. The dimensionality o f the fluctuations is also studied and it is found that they are predo minantly three dimensional near the transition with indications of cro ssover to two-dimensional behavior farther away.