Four-dimensional imaging of lattice dynamics using ab-initio simulation

Time-resolved mapping of lattice dynamics in real-and momentum-space is essential to better understand several ubiquitous phenomena such as heat transport,displacive phase transition,thermal conductivity,and many more.In this regard,time-resolved diffraction and microscopy methods are employed to image the induced lattice dynamics within a pump–probe configuration.In this work,we demonstrate that inelastic scattering methods,with the aid of theoretical simulation,are competent to provide similar information as one could obtain from the time-resolved diffraction and imaging measurements.To illustrate the robustness of the proposed method,our simulated result of lattice dynamics in germanium is in excellent agreement with the time-resolved x-ray diffuse scattering measurement performed using x-ray free-electron laser.For a given inelastic scattering data in energy and momentum space,the proposed method is useful to image in-situ lattice dynamics under different environmental conditions of temperature,pressure,and magnetic field.Moreover,the technique will profoundly impact where time-resolved diffraction within the pump–probe setup is not feasible,for instance,in inelastic neutron scattering.