The interlayer binding energy of hexagonal molybdenum disulfide at 0 K was calculated employing an exponential-six potential function summed over all sulfur neighbors across the interlayer gap. A rigid-layer, two-dimensional lattice model was assumed. Experimental values of the equilibrium lattice constants, the lattice constants under pressure, and the bulk modulus in the $c$ direction were used to determine the parameters of the potential. The interlayer binding energy was calculated to be -520 ± 40 erg/${\mathrm{cm}}^2$—giving a specific surface energy of —260 ± 20 erg/${\mathrm{cm}}^2$. The depth of the exponential-six potential (in temperature units) is 764 K, which is close to the temperature of an experimentally observed sintering process. The calculation was repeated using a Lennard-Jones potential, resulting in -490 ± 40 erg/${\mathrm{cm}}^2$ for the interlayer binding energy and a well depth of 703 K.

• Received 21 July 1976

DOI:https://doi.org/10.1103/PhysRevB.14.5392