Observation of Leggett's collective mode in a multiband MgB2 superconductor.

Authors :: Blumberg G
Mialitsin A
Dennis BS
Klein MV
Zhigadlo ND
Karpinski J
Source :: Physical review letters [Phys Rev Lett] 2007 Nov 30; Vol. 99 (22), pp. 227002. Date of Electronic Publication: 2007 Nov 29.
Publication Year :: 2007
Abstract: We report observation of Leggett's collective mode in a multiband MgB2 superconductor with Tc=39 K arising from the fluctuations in the relative phase between two superconducting condensates. The novel mode is observed by Raman spectroscopy at 9.4 meV in the fully symmetric scattering channel. The observed mode frequency is consistent with theoretical considerations based on first-principles computations.