Coherent dynamics of structural symmetry during the ultrafast melting of a charge density wave

Spiers Memorial Lecture: From optical to THz control of materials

“…Photon-driven electronic excitation across the CDW band gap shis this balance, leading to displacive excitation of the amplitude mode of the distortion or, at higher excitation levels, a transient phase change to an unmodulated "melted" state observable by optical spectroscopy and X-ray diffraction. [45][46][47][48][49] Electronic excitation has also been used to drive other kinds of structural symmetry changes in various materials. 50,51 Another new development in this arena is the interest in Higgs mode spectroscopy of superconductors, recently stimulated due to the ability to generate intense THz pulses suitable for nonlinear interactions at low frequencies.…”