Melting of Wigner crystal in high-mobility n-GaAs/AlGaAs heterostructures at filling factors 0.18 > ν> 0.125: Acoustic studies - I. L. Drichko; I. Yu. Smirnov; A. V. Suslov; Y. M. Galperin; L. N. Pfeiffer; K. W. West (2016)