Understanding Optomechanical properties of TaS2 from first principles

The 1T phase of tantalum disulfide, 1T-TaS2, is a layered van der Waal's material exhibiting commensurate charge density waves (CCDWs) that significantly alter its dielectric properties and are associated with a metal-insulator transition. Here, we utilize first-principles density functional theory (DFT) and time-dependent TDDFT to investigate the optomechanical response of 1T-TaS2. Simulations of the optical dielectric function show a transition from an anisotropic dielectric to a hyperbolic medium response in the visible frequency to mid-IR frequency regime. Additionally, we combine TDDFT simulations with a phenomenological model to describe the electron-phonon-mediated phase transition upon exposure to near- and mid-infrared pulsed illumination. We predict that the response of the material is highly sensitive to the wavelength and direction of the incoming far-field radiation.