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.com
Volume 7
Biosensors Journal
ISSN: 2090-4967
Electrochemistry 2018
June 11-12, 2018
June 11-12, 2018 | Rome, Italy
4
th
International Conference on
Electrochemistry
Linear response in topological semimetals
Yan Sun
Max Planck Institute for Chemical Physics of Solids, Germany
T
opological insulators have been expected to be ideal spintronic materials due to the spin currents carried by the surface
states with spin-momentum locking. However, the bulk doping problem still remains to be an obstacle that hinders such
application. While this kind of problem is naturally avoided in topological semimetals due to the large anomalous Hall and
spin Hall effect originated from the intrinsic bulk band structures. We have found that the strong spin Hall effect in TaAs is
mainly dominated from the Weyl points and nodal-line-like Fermi surface, which implying a strong interplay between the
topological band structure and Berry curvature in topological semimetals. With this guiding principle, we have successfully
understood the strong spin Hall effect in IrO
2
and found the nodal line band structures in it. Generalizing this principle to
time reversal symmetry breaking system, we have predicted strong anomalous Hall effect in magnetic Weyl semimetal CO
3
Sn
2
S
2
, which was verified by our experimental collaborators. Owing to the low charge carrier density and large Berry curvature
from the nodal line band structure, the anomalous Hall conductivity and anomalous Hall angle experimentally reach up to
1130 S/cm and 20% respectively. Further, the anomalous Hall effect can even exist with zero net moments in the absence of the
symmetry operation that changes the sign of Berry curvature. And the anomalous Hall effect can be strongly enhanced by the
special band structures of Weyl points and nodal lines. Following this guiding direction, we have predicted a strong anomalous
Hall effect in the compensated ferrimagnetic Weyl semimetal Ti
2
MnAl with vanishing magnetic net moments. Our work is
helpful for the comprehensive understanding of the linear response effect in topological materials and their future applications.
Figure 1:
Topological band structure induced anomalous Hall and spin Hall effect. a-b: Schematic of nodal line and Weyl semimetals. c: Schematic of anomalous
Hall and spin Hall effect. d: Berry curvature induced from the nodal line and Weyl points
Recent Publications:
1. Yan Sun, Yang Zhang, Claudia Felser, and Binghai Yan (2016) Phy. Rew. Lett. 117:146403.
2. Yan Sun, Yang Zhang, Chao Xing Liu, Claudia Felser and Binghai Yan (2017) Phy. Rew. B 95:235104.
3. E Liu, Y Sun, LMüchler, A Sun, L Jiao, J Kroder, VSüß, HBorrmann,WWang,WSchnelle, SWirth, S TBGoennenwein
and C Felser (2017) arXiv:1712.06722.
4. Wujun Shi, Lukas Muechler, Kaustuv Manna, Yang Zhang, Klaus Koepernik, Roberto Car, Jeroen van den Brink,
Claudia Felser and Yan Sun (2018) Phy. Rew. B 97:060406(R)
5. Jonathan Noky, Claudia Felser and Yan Sun (2018) arXiv:1803.03439
Biography
Yan Sun has his research interests mainly focus on the theatrical study of topological materials. Through the analysis of the relationship between Berry curvature
and band structure, we revealed strong spin Hall effect (SHE) and anomalous Hall effect (AHE) in WSMs and nodal line semimetals. The generalized relation
between SHE/AHE and topological band structure suggests a way of the application of topological semimetals in spintronics. Fundamentally, the intrinsic AHE just
depends on the symmetry of Berry curvature, but not the magnitude of net magnetic moments. Guiding by this principle, we have deeply studied two ideal strong
AHE systems with vanishing net magnetic moment, non-collinear antiferromagnets (Mn3Ge) and compensated ferrimagnetic WSM (Ti
2
MnAl)
yansunning@gmail.comYan Sun, Biosens J 2018, Volume 7
DOI: 10.4172/2090-4967-C1-002