Observation of Leggett's collective mode in a multiband MgB2 superconductor.
نویسندگان
چکیده
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.
منابع مشابه
Heat conduction in the vortex state of NbSe2: evidence for multiband superconductivity.
The thermal conductivity kappa of the layered s-wave superconductor NbSe2 was measured down to T(c)/100 throughout the vortex state. With increasing field, we identify two regimes: one with localized states at fields very near H(c1) and one with highly delocalized quasiparticle excitations at higher fields. The two associated length scales are naturally explained as multiband superconductivity,...
متن کاملLeggett modes in iron-based superconductors as a probe of time-reversal symmetry breaking
Since their discovery, it has been suggested that pairing in pnictides can be mediated by spin fluctuations between hole and electron bands. In this view, multiband superconductivity would substantially differ from other systems like MgB2, where pairing is predominantly intraband. Indeed, interband-dominated pairing leads to the coexistence of bonding and antibonding superconducting channels. H...
متن کاملBreak–junction Tunneling on Mgb 2
Tunneling data on magnesium diboride, MgB2, are reviewed with a particular focus on superconductor–insulator–superconductor (SIS) junctions formed by a break–junction method. The collective tunneling literature reveals two distinct energy scales, a large gap, ∆L ∼ 7.2 meV, close to the expected BCS value, and a small gap, ∆S ∼ 2.4 meV. The SIS break junctions show clearly that the small gap clo...
متن کاملMultiband model for tunneling in MgB2 junctions
A theoretical model for quasiparticle and Josephson tunneling in multiband superconductors is developed and applied to MgB2-based junctions. The gap functions in different bands in MgB2 are obtained from an extended Eliashberg formalism, using the results of band structure calculations. The temperature and angle dependencies of MgB2 tunneling spectra and the Josephson critical current are calcu...
متن کاملMicrowave response of a cylindrical cavity made of bulk MgB 2 superconductor
We report on the microwave properties of a resonant cylindrical cavity made of bulk MgB2 superconductor, produced by the reactive liquid Mg infiltration process. The frequency response of the cavity has been measured in the range 5÷ 13 GHz. Among the various modes, the TE011, resonating at 9.79 GHz, exhibits the highest quality factor. For this mode, we have determined the temperature dependenc...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review letters
دوره 99 22 شماره
صفحات -
تاریخ انتشار 2007