Liu, T.-M.T.-M.LiuYang, M.-J.M.-J.YangLai, C.-W.C.-W.LaiPI-TAI CHOUChang, M.-H.M.-H.ChangLiu, H.-L.H.-L.LiuCHI-KUANG SUN2018-09-102018-09-10200810980121http://www.scopus.com/inward/record.url?eid=2-s2.0-40849087985&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/340702https://www.scopus.com/inward/record.uri?eid=2-s2.0-40849087985&doi=10.1103%2fPhysRevB.77.085428&partnerID=40&md5=fe37c73d5d72cbb76dc1bc245342f538We report here the observation of piezoelectricity-induced terahertz photon absorption related to confined acoustic phonons in nanoparticles. Terahertz photon inactive (l=0) breathing modes become terahertz photon active in wurtzite CdSe nanocrystals due to the piezoelectric coupling. Obvious absorption peaks related to (l=0) modes appeared in the terahertz absorption spectra and the frequency of the peaks were inversely proportional to the size of the CdSe nanocrystals. This piezoelectrically coupled electric vibration provides a mechanism for low-dimensional systems to convert a terahertz photon into a phonon of the same frequency. © 2008 The American Physical Society.[SDGs]SDG7journal article10.1103/PhysRevB.77.0854282-s2.0-40849087985WOS:000253764300111