Raman spectra of MgB2 at high pressure and topological electronic transition

Abstract

Raman spectra of the MgB2 ceramic samples were measured as a function of pressure up to 32 GPa at room temperature. The spectrum at normal conditions contains a very broad peak at ~590 cm-1 related to the E2g phonon mode. The frequency of this mode exhibits a strong linear dependence in the pressure region from 5 to 18 GPa, whereas beyond this region the slope of the pressure-induced frequency shift is reduced by about a factor of two. The pressure dependence of the phonon mode up to ~ 5GPa exhibits a change in the slope as well as a "hysteresis" effect in the frequency vs. pressure behavior. These singularities in the E2g mode behavior under pressure support the suggestion that MgB2 may undergo a pressure-induced topological electronic transition.

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Cited by in corpus (6)

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• Pressure-dependent Semiconductor to Semimetal and Lifshitz transitions in 2H-MoTe${}_2$: Raman and First-principles studies
• Possible superlattice formation in high-temperature treated carbonaceous MgB2 at elevated pressure
• Pressure Effects and Large Polarons in Layered MgB_2 Superconductor