Observing vortex polarization singularities at optical band degeneracies
Ang Chen, Wenzhe Liu, Yiwen Zhang, Bo Wang, Xiaohan Liu, Lei Shi, Ling Lu, and Jian Zi
Phys. Rev. B 99, 180101(R) (2019) - Published 6 May, 2019
Photoinduced dynamics of nematic order parameter in FeSe
T. Konstantinova, L. Wu, M. Abeykoon, R. J. Koch, A. F. Wang, R. K. Li, X. Shen, J. Li, J. Tao, I. A. Zaliznyak, C. Petrovic, S. J. L. Billinge, X. J. Wang, E. S. Bozin, and Y. Zhu
Phys. Rev. B 99, 180102(R) (2019) - Published 28 May, 2019
Nematicity is deemed a precursor of superconductivity in unconventional superconductors. Here, the authors investigate the formation of a nematic phase and the dynamics of nematic fluctuations in FeSe using ultrafast electron diffraction. They find an enhancement of the high-symmetry crystalline order as a result of photoinduced suppression of low-symmetry local lattice distortion. This distortion, which is a signature of nematic fluctuations, is corroborated by x-ray pair distribution function analysis and electron microscopy, and is present in a wide temperature range below and above the nematic phase transition.





