【摘要】 测量了多晶MgB2 的热导 ,实验温区为 5— 30 0K .在双能隙模型下 ,用基于BCS超导理论的BRT热导理论对实验结果进行了分析 ,给出MgB2 中两个能隙大小分别为 1 6和 5 1meV .对电子热导的分析结果表明σ能带准粒子受到的杂质散射远小于π能带准粒子受到的杂质散射 .与单晶MgB2 的热导实验结果相比 ,多晶MgB2 的声子热导结果表明在c方向上热传导声子受到来自σ能带准粒子的散射 ,显示了MgB2 在能量输运上的各向异性 .更多还原

【Abstract】 We present in this paper the thermal conductivity of the superconductor MgB 2 between 5—300 K. The temperature dependence of the thermal conductivity can be fitted with the BRT thermal conductivity method by a phenomenological two gap model. The sizes of the two energy gaps are 1 6 and 5 1meV. The analysis about electronic thermal conductivity indicates that the σ band impurity scattering rate is small relative to the π band scattering rate. In contrast to the single crystal sample, our result indicates that the scattering of phonons from the σ band quasi particles exist in the c axial direction heat transport of a polycrystalline sample. This result demonstrates the anisotropic energy transport in MgB 2.更多还原