Electron-phonon effects on the Raman spectrum in Mg B 2
Electron-phonon effects on the Raman spectrum in Mg B 2
复制标题
电子声子对 Mg B 2 拉曼光谱的影响
DOI：
10.1103/physrevb.73.140505
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发表时间：
2005
影响因子：
3.7
通讯作者：
E. Cappelluti
中科院分区：
文献类型：
--
作者：
E. Cappelluti
The anomalous features of the Raman spectroscopy measurement in $\mathrm{Mg}{\mathrm{B}}_{2}$ represent a still unresolved puzzle. In particular, highly debated are the origin of the huge ${E}_{2g}$ phonon linewidth, the nature of the low energy $(\ensuremath{\omega}l{\ensuremath{\omega}}_{{E}_{2g}})$ background and the evolution of the Raman spectra with Al doping. In this paper we compute the self-energy of the ${E}_{2g}$ phonon mode in a fully self-consistent way, taking into account electron-phonon effects on the electronic properties. We show that all the anomalous features can be naturally understood in a framework where the whole electron-phonon spectrum ${\ensuremath{\alpha}}^{2}F(\ensuremath{\omega})$ gives rise to significant damping processes for the electronic excitations and consequently for the ${E}_{2g}$ phonon itself. The two-peak structure as function of the Al doping is ascribed to finite bandwidth effects arising as the Fermi level approaches the $\ensuremath{\sigma}$ band edge.
The anomalous features of the Raman spectroscopy measurement in $\mathrm{Mg}{\mathrm{B}}_{2}$ represent a still unresolved puzzle. In particular, highly debated are the origin of the huge ${E}_{2g}$ phonon linewidth, the nature of the low energy $(\ensuremath{\omega}l{\ensuremath{\omega}}_{{E}_{2g}})$ background and the evolution of the Raman spectra with Al doping. In this paper we compute the self-energy of the ${E}_{2g}$ phonon mode in a fully self-consistent way, taking into account electron-phonon effects on the electronic properties. We show that all the anomalous features can be naturally understood in a framework where the whole electron-phonon spectrum ${\ensuremath{\alpha}}^{2}F(\ensuremath{\omega})$ gives rise to significant damping processes for the electronic excitations and consequently for the ${E}_{2g}$ phonon itself. The two-peak structure as function of the Al doping is ascribed to finite bandwidth effects arising as the Fermi level approaches the $\ensuremath{\sigma}$ band edge.