Influence of strain on specific features of MoX2 (X = S, Se, Te) monolayers

We employ the full-potential linearized augmented plane wave (FLAPW) method as implemented in the WIEN2k code for calculating structural, electronic, vibrational and photocatalytic properties of strained MoS2, MoSe2 and MoTe2 monolayers. Compressive strain of 1.5% for MoS2, 1% for MoSe2, and 1.5% for MoTe2, transform their band gaps from direct to indirect, while in case of tensile strain the nature of band gap remains direct. Under compressive strain size of the band gap passes through a maximum and decreases monotonically under tensile strain. A remarkable valence band splitting is found for all three compounds, which is further modified by strain. Mobility of electron are also calculated and found to be vary under strain. Photocatalytic properties show that unstrained and respective strained MoS2 and MoSe2 systems are higher than the H2O/O-2 potential, showing that H2O can be oxidized to O-2, while MoTe2 fail to oxidized H2O to O-2. Furthermore phonon spectra suggest that these systems are stable under both compressive and tensile strain.