Ultrafast optical stress on BaFe_{2}As_{2}

• Published in: Physical review research Vol. 3; no. 3; p. 033222
• Main Authors: Takeshi Suzuki, Yuya Kubota, Asuka Nakamura, Takahiro Shimojima, Kou Takubo, Suguru Ito, Kohei Yamamoto, Shoya Michimae, Hikaru Sato, Hidenori Hiramatsu, Hideo Hosono, Tadashi Togashi, Makina Yabashi, Hiroki Wadati, Iwao Matsuda, Shik Shin, Kozo Okazaki
• Format: Journal Article
• Language: English
• Published: American Physical Society 01.09.2021
• ISSN: 2643-1564
• DOI: 10.1103/PhysRevResearch.3.033222

We investigate the ultrafast lattice dynamics in BaFe_{2}As_{2} via time-resolved x-ray diffraction measurements using an x-ray free-electron laser at SPring-8 Angstrom Compact free-electron LAser (SACLA). The profile of the Bragg peaks substantially changes after strong photoexcitation, where the c axis length of the lattice initially contracts, followed by expansion. These ultrafast lattice contractions and expansions significantly depend on the pump fluence, and it is suggested that a strong normal stress is applied along the c axis. To obtain a phenomenological understanding of the observed lattice dynamics, we performed calculations based on a two-temperature model and an ultrafast thermoelasticity model. Our results showed that a steep gradient of the electron temperature induced by photoexcitation generates a blast force, which acts as a strong normal stress. We propose that a temporal stress can be applied by a strong optical pump, and this scheme can be another route for the application of uniaxial stress to superconductors.