X-ray and optical investigation of the charge density wave in K0.3MoO3 | Rafael Winkler (ETH Zurich)

Speaker: Rafael Winkler (ETH Zürich)

Host: Denitsa Baykusheva

Charge density waves (CDW) occur due to Peierls instability and strong electron-phonon interaction in condensed matter systems. Their formation results in a change of the electronic band structure as well in a periodic distortion of the underlying lattice. While the electronic contributions to the CDW can be studied with optical spectroscopy, the underlying lattice distortion can be investigated using x-ray diffraction. These methods are also suitable to investigate the dynamics of the CDW using ultrafast laser and x-ray pulses to excite and probe the material.

In this talk I will present our results on K_0.3MoO₃ where we excited and destroyed the CDW with ultra short laser pulses and probed its dynamics with time-resolved x-ray diffraction done at SwissFEL. The measurements reveal a transient flip of the phase of the CDW which disappears in less than 1 ps. Furthermore, our optical pump probe measurements show an interesting behaviour of the observed phonon modes that might be in line with the transient phase flip of the CDW.