Spectroscopic evidence for anisotropic s -wave pairing symmetry in MgB 2
2001; American Physical Society; Volume: 65; Issue: 1 Linguagem: Inglês
10.1103/physrevb.65.012505
ISSN1095-3795
AutoresPierre Sénéor, C.-T. Chen, N.-C. Yeh, R. P. Vasquez, L. D. Bell, C. U. Jung, Min‐Seok Park, Heon‐Jung Kim, Won Nam Kang, Sung‐Ik Lee,
Tópico(s)Iron-based superconductors research
ResumoScanning tunneling spectroscopy of superconducting ${\mathrm{MgB}}_{2}$ ${(T}_{c}=39 \mathrm{K})$ were studied on high-density pellets and c-axis oriented films. The sample surfaces were chemically etched to remove surface carbonates and hydroxides, and the data were compared with calculated spectra for all symmetry-allowed pairing channels. The pairing potential $({\ensuremath{\Delta}}_{k})$ is best described by an anisotropic s-wave pairing model, with ${\ensuremath{\Delta}}_{k}={\ensuremath{\Delta}}_{\mathrm{xy}}{\mathrm{sin}}^{2}{\ensuremath{\theta}}_{k}+{\ensuremath{\Delta}}_{z}{\mathrm{cos}}^{2}{\ensuremath{\theta}}_{k},$ where ${\ensuremath{\theta}}_{k}$ is the angle relative to the crystalline c-axis, ${\ensuremath{\Delta}}_{z}\ensuremath{\sim}8.0 \mathrm{meV},$ and ${\ensuremath{\Delta}}_{\mathrm{xy}}\ensuremath{\sim}5.0 \mathrm{meV}.$
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