Karapetrov G, Iavarone M, Kwok W K, Crabtree G W, Hinks D G
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Phys Rev Lett. 2001 May 7;86(19):4374-7. doi: 10.1103/PhysRevLett.86.4374.
We present scanning tunneling microscopy measurements of the surface of superconducting MgB2 with a critical temperature of 39 K. In zero magnetic field the conductance spectra can be analyzed in terms of the standard BCS theory with a smearing parameter gamma. The value of the superconducting gap is 5 meV at 4.2 K, with no experimentally significant variation across the surface of the sample. The temperature dependence of the gap follows the BCS form, fully consistent with phonon-mediated superconductivity in this novel superconductor. The application of a magnetic field induces strong pair breaking as seen in the conductance spectra in fields up to 6 T.
我们展示了对临界温度为39K的超导MgB₂表面的扫描隧道显微镜测量结果。在零磁场中，电导谱可以根据具有展宽参数γ的标准BCS理论进行分析。在4.2K时超导能隙的值为5毫电子伏特，在样品表面上没有实验上显著的变化。能隙的温度依赖性遵循BCS形式，与这种新型超导体中声子介导的超导性完全一致。如在高达6T磁场中的电导谱所示，施加磁场会引起强烈的对破坏。
