Ultrafast Modulations and Detection of a Ferro-Rotational Charge Density Wave Using Time-Resolved Electric Quadrupole Second Harmonic Generation

Xiangpeng Luo; Dimuthu Obeysekera; Choongjae Won; Suk Hyun Sung; Noah Schnitzer; Robert Hovden; Sang-Wook Cheong; Junjie Yang; Kai Sun; Liuyan Zhao

doi:10.1103/PhysRevLett.127.126401

Ultrafast Modulations and Detection of a Ferro-Rotational Charge Density Wave Using Time-Resolved Electric Quadrupole Second Harmonic Generation

Phys Rev Lett. 2021 Sep 17;127(12):126401. doi: 10.1103/PhysRevLett.127.126401.

Authors

Xiangpeng Luo¹, Dimuthu Obeysekera², Choongjae Won³, Suk Hyun Sung⁴, Noah Schnitzer⁴, Robert Hovden⁴, Sang-Wook Cheong^{3

5}, Junjie Yang², Kai Sun¹, Liuyan Zhao¹

Affiliations

¹ Department of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, USA.
² Department of Physics, New Jersey Institute of Technology, 323 Dr Martin Luther King Jr Blvd, Newark, New Jersey 07102, USA.
³ Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea.
⁴ Department of Materials Sciences, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA.
⁵ Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA.

PMID: 34597104
DOI: 10.1103/PhysRevLett.127.126401

Abstract

We show the ferro-rotational nature of the commensurate charge density wave (CCDW) in 1T-TaS_{2} and track its dynamic modulations by temperature-dependent and time-resolved electric quadrupole rotation anisotropy-second harmonic generation (EQ RA-SHG), respectively. The ultrafast modulations manifest as the breathing and the rotation of the EQ RA-SHG patterns at three frequencies around the reported single CCDW amplitude mode frequency. A sudden shift of the triplet frequencies and a dramatic increase in the breathing and rotation magnitude further reveal a photoinduced transient CDW phase across a critical pump fluence of ∼0.5 mJ/cm^{2}.