Strong interaction between electrons and collective excitations in the multiband superconductor MgB2
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Abstract
We use a tunable laser angle-resolved photoemission spectroscopy to study the electronic properties of the prototypical multiband BCS superconductor MgB2. Our data reveal a strong renormalization of the dispersion (kink) at ∼65meV, which is caused by the 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 a binding energy of 10 meV. This excitation vanishes above Tc and is likely a signature of the elusive Leggett mode.
Comments
This article is published as Mou, Daixiang, Rui Jiang, Valentin Taufour, Rebecca Flint, S. L. Bud'ko, P. C. Canfield, J. S. Wen, Z. J. Xu, Genda Gu, and Adam Kaminski. "Strong interaction between electrons and collective excitations in the multiband superconductor MgB 2." Physical Review B 91, no. 14 (2015): 140502. DOI: 10.1103/PhysRevB.91.140502. Posted with permission.