Photoinduced domain walls and transient charge density waves in rare earth tri-tellurides

Mariano Trigo

(SLAC National Accelerator Lab)

Gal Orenstein

(Stanford University)

Quynh Nguyen

(Stanford University)

Viktor Krapivin

(Stanford University)

Gilberto De La Peña

(Stanford University)

Ryan Duncan

(Stanford University)

Samuel Teitelbaum

(Arizona State University)

Anisha G. Singh

(Stanford University)

Roman Mankowsky

(Paul Scherrer Institute)

Mathias Sander

(Paul Scherrer Institute)

Henrik Lemke

(Paul Scherrer Institute)

David. A. Reis

(Stanford University)

Ian R. Fisher

(Stanford University)

We use ultrafast x-ray diffraction to investigate the dynamics of transient charge density waves (CDW) in SmTe3 and LaTe3. We show that strong photoexcitation can invert the amplitude of the CDW near the surface resulting in reproducible photoinduced domain walls, which are responsible for the suppression of the diffraction intensity. This is likely a universal phenomenon that affects most ultrafast experiments in charge-ordered systems. Furthermore, we show that in both materials, suppression of the stable CDW order (along the c-axis) induces a transient enhancement of the intensity at a perpendicular wavevector (the a-axis) in momentum space with a timescale of a few picoseconds. This enhancement may indicate a transient tendency towards ordering along the a-axis and a signature of competition between these CDWs. However, our high wavevector resolution shows that the transient a-order does not develop over long range.