Chiral anomaly in Weyl semimetals and hidden orbital polarization in centrosymmetric materials
CFM Seminars
- Speaker
-
Cheol-Hwan Park (Seoul National University)
- When
-
2017/08/30
14:00 - Place
- CFM seminar room
- Add to calendar
- iCal
After the discovery by Zhang et al. [Nature Phys. 10, 387-393 (2014)] of
hidden spin polarizations in non-magnetic, centrosymmetric materials,
the scope of spintronics has been broadened to systems with PT symmetry.
In the first part of the talk, I will discuss the orbital version of
this physics, the hidden orbital polarization [1]. Hidden orbital
polarization is much more abundant in nature than the spin counterpart
since no spin-orbit coupling is required and is responsible for the
generation of hidden spin polarization via spin-orbit coupling. We look
into materials like diamond, silicon and transition metal
dichalcogenides.
In the second part of the talk, I will discuss the chiral anomaly in
Weyl semimetals, an imbalance in the charge carriers with opposite
chiralities [2]. Through our first-principles calculations, we show that
a sizable energy gap may open up at the intersection of the zeroth
Landau levels originating from opposite-chirality Weyl points. These
zeroth Landau levels have so far believed to remain gapless in Weyl
semimetals.
[1] Ji Hoon Ryoo and Cheol-Hwan Park, "Hidden orbital polarization in
diamond, silicon, germanium, gallium arsenide and layered materials",
NPG Asia Materials 9, e382 (2017).
[2] Pilkwang Kim, Ji Hoon Ryoo and Cheol-Hwan Park, "Chiral anomaly in
Weyl semimetals is not robust", arXiv:1707.01103.