Manipulation of electron-phonon energy transfer pathways in 2D transition metal dichalcogenides through ultrafast excitation

The complex phase landscape of quantum materials provides tremendous opportunity for design, manipulation, and coherent control of material properties using light. Understanding that complexity also poses a significant challenge, and multiple techniques are needed to map and exploit the rich phase space of strongly correlated materials. For example, using ultrafast electron calorimetry via time- and angle-resolved photoemission (ARPES), a bi-directional energy transfer between strongly-correlated electron and phonon modes in a material has been observed for the first time - in this case a charge density wave (CDW) material 1T-TaSe2.
Here we use visible pump-probe spectroscopy to further explore and manipulate the couplings between the electron and phonon systems. By varying the pump fluence, we can alter the relative coupling strength of multiple phonon modes, demonstrating the use of light to control material properties and select available vibrational relaxation pathways in quantum materials.