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Spectroscopic Evidence for Anisotropic S-Wave Pairing Symmetry in MgB2

P. Seneor·C. -T. Chen·N. -C. Yeh·R. P. Vasquez·L. D. Bell·C. U. Jung·Min-Seok Park·Heon-Jung Kim·W. N. Kang·Sung-Ik Lee
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Abstract

Scanning tunneling spectroscopy of superconducting MgB$_2$ ($T_c = 39$ 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 ($Δ_k$) is best described by an anisotropic s-wave pairing model, with $Δ_k = Δ_{xy} \sin ^2 θ_k + Δ_z \cos ^2 θ_k$, where $θ_k$ is the angle relative to the crystalline c-axis, $Δ_z \sim 8.0$ meV, and $Δ_{xy} \sim 5.0$ meV.

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P. Seneor, C. -T. Chen, N. -C. Yeh, R. P. Vasquez, L. D. Bell, C. U. Jung, Min-Seok Park, Heon-Jung Kim, W. N. Kang, Sung-Ik Lee. 2001-08-13. Spectroscopic Evidence for Anisotropic S-Wave Pairing Symmetry in MgB2. https://doi.org/10.1103/physrevb.65.012505

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