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arXiv · 1503.07069

Strong interaction between electrons and collective excitations in multiband superconductor MgB2

Daixiang Mou·Rui Jiang·Valentin Taufour·Rebecca Flint·S. L. Budko·P. C. Canfield·J. S. Wen·Z. J. Xu·Genda Gu·Adam Kaminski
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Abstract

We use a tunable laser ARPES to study the electronic properties of the prototypical multiband BCS superconductor MgB2. Our data reveal a strong renormalization of the dispersion (kink) at ~65 meV, which is caused by coupling of electrons to the E2g phonon mode. In contrast to cuprates, the 65 meV kink in MgB2 does not change significantly across Tc. More interestingly, we observe strong coupling to a second, lower energy collective mode at binding energy of 10 meV. This excitation vanishes above Tc and is likely a signature of the elusive Leggett mode.

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Daixiang Mou, Rui Jiang, Valentin Taufour, Rebecca Flint, S. L. Budko, P. C. Canfield, J. S. Wen, Z. J. Xu, Genda Gu, Adam Kaminski. 2015-03-24. Strong interaction between electrons and collective excitations in multiband superconductor MgB2. https://doi.org/10.1103/physrevb.91.140502

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