Strain-shear coupling in bilayer MoS2

• DOI: 10.1038/s41467-017-01487-3
• Publication Date: 2017-11-03T11:17:17Z
• Authors: Jae-Ung Lee; Sungjong Woo; Jaesung Park; Hee Chul Park; Young-Woo Son; Hyeonsik Cheong
• Keywords: Condensed Matter - Materials Science; Science; Q; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences; Article; 0104 chemical sciences

Abstract Layered materials such as graphite and transition metal dichalcogenides have extremely anisotropic mechanical properties owing to orders of magnitude difference between in-plane out-of-plane interatomic interaction strengths. Although effects perturbations on either intralayer or interlayer interactions been extensively investigated, mutual correlations them rarely addressed. Here, we show that layered an inevitable coupling uniaxial strain shear. Because this, the induces anomalous splitting degenerate shear phonon modes split mode along tensile is not softened but hardened contrary case modes. We confirm effect by measuring Raman shifts bilayer MoS 2 under strain. Moreover, analyzing splitting, obtain unexplored off-diagonal elastic constant, demonstrating spectroscopy can determine almost all constants materials.