| 날짜 | 2022-01-11 15:00 |
|---|---|
| 일시 | Jan. 11th(Tue), 15:00 |
| 장소 | E6 #1501 |
| 연사 | Soyeun Kim(UIUC) |
Physics Seminar
“Ultrafast optical studies on CDW collective modes of the Weyl-CDW (TaSe4)2I”
Soyeun Kim
Department of Physics,
Univ. Illinois at Urbana-Champaign (UIUC)
Jan. 11th (Tue), 15:00, E6 #1501
(TaSe4)2I provides an excellent platform to explore topology, lattice, and charge degrees of freedom. It is a non-magnetic Weyl semimetal with a quasi-1D charge-density wave phase transition (TC ~ 260 K) on its structurally chiral lattice. Because the pairs of Weyl fermions are coupled by a CDW modulation, the phase part of the CDW collective mode is suggested to follow the axion electrodynamics described by θE·B [1,2]. As a result, exciting phenomena such as negative magnetoresistance, quantized photogalvanic and piezomagnetic effects have been proposed [1,3,4]. In this talk, we will investigate the CDW collective modes of (TaSe4)2I using ultrafast optical tools of THz emission and THz-pump birefringence spectroscopy. The experimental results will be discussed and compared to the theoretically suggested magnetoelectric effects in the Weyl-CDW system.
[1] J. Gooth et al., Nature 575, 315 (2019).
[2] W. Shi et al., Nat. Phys. 17, 381 (2021).
[3] D. M. Nenno et al., Nat. Rev. Phys. 2, 682 (2020).
[4] Yu et al., Phys. Rev. B 104, 174406 (2021).
Contact: Eunjung Jo, (jojo@kaist.ac.kr)