Jan. Switching handedness of of chiral solitons in Z4 topological insulators

Dr. Tae-Hwan KIM (POSTECH)

Mar. 11 (Fri.), 4:00 PM, E6-2. 1st fl. #1501

Chirality is a ubiquitous and interesting phenomenon in fields ranging from biology, chemistry to physics. In condensed matter, chirality can be topologically protected by the system’s symmetry and thus can be used to carry information robustly against external perturbations. For instance, magnetic skyrmions have been investigated intensively as topological information carriers for next generation spintronic devices. However, logic operations using topological excitations are only conceptually proposed. On the other hand, chiral solitons are recently discovered as the topologically protected edge states of one-dimensional Z4 topological insulators [1,2], which can be exploited as topological information carriers in electronic system. In this talk, I show experimentally and directly that switching between solitons with different chirality is possible by merging them with achiral soliton [3]. This switching corresponds to the realization of topological addition of the Z4 topological number. With their distinct topologically protected chirality, chiral solitons could uniquely be exploited for robust multilevel information storage and logic operation by storing, carrying, and switching three differently topological bits of information.

[1] T.-H. Kim and H. W. Yeom, Phys. Rev. Lett. 109, 246802 (2012).
[2] S. Cheon, T.-H. Kim, S.-H. Lee, and H. W. Yeom, Science 350, 182 (2015).
[3] T.-H. Kim et al. to be submitted

Contact: Heung Sun Sim, Physics Dept., (hs_sim@kaist.ac.kr)