Interlayer interaction in 2H-MoTe2/hBN heterostructures

초록

Interlayer vibrational modes in 2H-MoTe2/hBN heterostructures were investigated by low-frequency Raman spectroscopy. A series of low-frequency Raman modes are observed for MoTe2 thicknesses of 1-4 layers: the shear modes of MoTe2 persist in the heterostructure with no shift in the frequency, but the breathing modes show dramatic changes in the heterostructures. The number and the frequencies of the breathing modes do not depend on the twist angle between the two materials but strongly vary with the layer thicknesses of both MoTe2 and hBN layers. The breathing modes were observed for both resonant (1.96 eV) and non-resonant (2.41 eV) excitations. The breathing mode frequencies were analyzed by using the linear chain model, and the interfacial force constant between 2 H-MoTe2 and hBN is estimated to be 3.77 x 10(19) N m(-3).

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