Collective excitations

Ravichandran, J, A.K Yadav, R Cheaito, P.B Rossen, A Soukiassian, S.J Suresha, J.C Duda, B.M Foley, C.-H Lee, Y Zhu, A.W Lichtenberger, J.E Moore, D.A Muller, D.G Schlom, P.E Hopkins, A Majumdar, Ramamoorthy Ramesh, and M.A Zurbuchen. "Crossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices." Nature Materials 13 (2014) 168–172.