Tuning topological disorder in MgB$_{2}$

D. Di Castro; E. Cappelluti; M. Lavagnini; A. Sacchetti; A. Palenzona; M. Putti; P. Postorino

doi:10.1103/physrevb.74.100505

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Tuning topological disorder in MgB$_{2}$

D. Di Castro·E. Cappelluti·M. Lavagnini·A. Sacchetti·A. Palenzona·M. Putti·P. Postorino

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Abstract

We carried out Raman measurements on neutron-irradiated and Al-doped MgB$_2$ samples. The irradiation-induced topological disorder causes an unexpected appearance of high frequency spectral structures, similar to those observed in lightly Al-doped samples. Our results show that disorder-induced violations of the selection rules are responsible for the modification of the Raman spectrum in both irradiated and Al-doped samples. Theoretical calculations of the phonon density of states support this hypothesis, and demonstrate that the high frequency structures arise mostly from contributions at ${\bf q}\not=0$ of the E$_{2g}$ phonon mode.

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D. Di Castro, E. Cappelluti, M. Lavagnini, A. Sacchetti, A. Palenzona, M. Putti, P. Postorino. 2006-02-21. Tuning topological disorder in MgB$_{2}$. https://doi.org/10.1103/physrevb.74.100505

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