Resonant Raman scattering at exciton states tuned by pressure and temperature in 2H-MoS2

We report on the temperature and pressure dependence of Stokes and anti-Stokes Raman spectra of a single crystal of 2H-MoS2 as the energies of the A(1) and B-1 excitons, E-A1 and E-B1, are tuned to resonate with an exciting laser at E-L = 1.96 eV. Pressure-and temperature-dependent intensity ratio analysis of the resonant A(1g) phonon and the E-2g(1) phonon is complemented by the calculation of resonance Raman probability profiles of the former, which well agree with experiments. The temperature-dependent proximity of E-A1 and E-B1 to E-L is reflected in the formation of Stokes dominated A(1) and anti-Stokes dominated B-1 temperature zones with a midpoint positioned at T similar to 260 K. The shift in the frequency of the Stokes two-phonon dispersive band relative to that of the anti-Stokes band is explained as due to changing in the order of participation of the quasiacoustic phonon in the scattering process.