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arXiv · 2103.14832

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
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Abstract

We show the ferro-rotational nature of the commensurate charge density wave (CCDW) in $1T$-$\mathrm{TaS}_2$ 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 photo-induced transient CDW phase across a critical pump fluence of ~ 0.5 mJ/cm$^2$.

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Xiangpeng Luo, Dimuthu Obeysekera, Choongjae Won, Suk Hyun Sung, Noah Schnitzer, Robert Hovden, Sang-Wook Cheong, Junjie Yang, Kai Sun, Liuyan Zhao. 2021-06-06. Ultrafast Modulations And Detection of a Ferro-rotational Charge Density Wave Using Time-resolved Electric Quadrupole Second Harmonic Generation. https://doi.org/10.1103/physrevlett.127.126401

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