Observation of Ultrafast Dynamics of Charge Density Wave Order in LaAgSb₂

Abstract

　In order to elucidate the nature of charge density wave (CDW) order in LaAgSb₂, we have performed an ultrafast pump and probe x-ray diffraction experiment at BL3 in SACLA. CDW reflection 1-τ₁ 0 7 was observed in a geometry that the incident x-ray beam was inclined to the sample surface at sample temperature T = 80 K, which is low enough for the CDW transition. The effect of the optical pump laser on the intensity and the width of CDW reflection 1-τ₁ 0 7 was unclear because of the low count rate and the crystal quality of the sample surface. In the same way, the integrated intensity of the CDW reflection 1-τ₁ 0 7 did not show any signature of CDW order melting as a function of the time delay to the pump laser pulse with a high fluence.