Influence of isotopic substitution on the anharmonicity of the interlayer shear mode of h -BN

This work has been supported by the Spanish MINECO/FEDER under Contract No. MAT2015-71035-R. B.G. acknowledges the Russian Megagrant program (Ioffe Institute of RAS, Contract No. 14.W03.31.0011). Support for the h -BN crystal growth from the Materials Engineering and Processing program of the National Science Foundation, Award No. CMMI 1538127, is greatly appreciated.