| Co-Investigator(Kenkyū-buntansha) |
MOMONO Naoki Hokkaido Univ., Grad. School of Sci., Inst., 大学院・理学研究科, 助手 (00261280)
IDO Masayuki Hokkaido Univ., Grad. School of Sci., Pro., 大学院・理学研究科, 教授 (90111145)
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| Research Abstract |
In the present study, we have been obtained the following results.
1) In Bi2212 and La214, the low temperature (T<<TィイD2cィエD2) energy gap 2ΔィイD2oィエD2 increases with the lowering of the hole doping level p and scales with pseudogap temperature TィイD1*ィエD1 over a wide p range; TィイD1*ィエD1 is comparable to the mean-fieid TィイD2cィエD2(TィイD2coィエD2). This result provides a strong evidence for the pseudogap being related to the high-TィイD2cィエD2 superconductivity.
2) On the basis of the dependences of electronic specific heat and magnetic susceptibility, it was found that the superconducting critical fluctuation develops markedly below a certain temperature TィイD2sf' ィエD2, 〜20% higher than TィイD2cィエD2 and much lower than TィイD1*ィエD1〜TィイD2coィエD2. This suggests that the motion of singlet pairs, whose formation will give rise to the pseudogap below 〜TィイD1*ィエD1, tends to become coherent below 〜TィイD2sfィエD2 to establish long-range phase coherence at TィイD2cィエD2.
3) In Bi2212 and La214, TィイD2cィエD2 nearly scales with pΔィイD2oィエD2 ; kィイD2BィエD2TィイD2cィエD2〜pΔィイD2oィエD2. This indicates that the energy scale in determining TィイD2cィエD2, is of the order of pΔィイD2oィエD2, which is a striking feature of high-TィイD2cィエD2 cuprates, differing from that expected in conventional superconductors.
In the present study, a scenario for the superconducting transition mechanism has also been proposed on the basis of the results mentioned above.
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