Effect of morphology and stacking on atomic interaction and magnetic characteristics in two-dimensional H-phase VS2 few layers

Recently, the research of two-dimensional layered transition metal dichalcogenides has made great progress due to their high potential in advanced electronic devices. In this work, H-phase VS2 atomic layers with different morphologies and stacking orders were successfully synthesized on sapphire via chemical vapor deposition. The H-phase VS2 shows semiconductor characteristic with its valence band maximum located ~ 0.25 eV below the Fermi level. Interlayer many-body interactions are strongly stacking-dependent, leading to distinguished intensity ratio between the breathing and shear modes, 2.99 ± 0.94 for AA, and 1.72 ± 0.26 for AB stacking. The intralayer S-V interaction (force constant: 2.80–3.54 × 1021 N/m3) is two orders of magnitude larger than the interlayer S–S interaction (force constant: 1.98–6.70 × 1019 N/m3). The shear modulus is further derived to be ~ 12.8 GPa, ~ 30% smaller than that of MoS2. The prepared VS2 film exhibits obvious magnetic behavior at room temperature with the attenuation distance of ~ 16–25 nm in out-of-plane direction. The morphology dependent magnetism and stability investigations indicate that the measured magnetic behaviors of the sample have a certain degree of extrinsic contributions, which may settle down some experimental controversies about the magnetic behaviors in this specific system.