Which mechanism causes significant acoustic phonon scattering in nanocrystalline graphene?

💡 Explanation

Nanocrystalline graphene's smaller grain sizes trigger increased phonon scattering because grain boundaries disrupt the crystal lattice. This encourages Umklapp scattering, which drastically reduces thermal conductivity, therefore acoustic phonon scattering elevates; rather than other factors like spin-orbit effects being principal.

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