Serra-Garcia, MPeri, VSusstrunk, RBilal, ORLarsen, TVillanueva, LGHuber, SD2018-11-082018-11-082018-11-08201810.1038/nature25156https://infoscience.epfl.ch/handle/20.500.14299/150691WOS:000427477100030Observation of a phononic quadrupole topological insulatortext::journal::journal article::research article