Spin, parity, chirality and topology in quantum matters
일 시 : 2022년 01월 13일 목요일 10:00
연 사 : 양 시 훈 박사 (Infinite Solutions and IBM Research – Almaden)
장 소 : 온라인 (https://us02web.zoom.us/j/83446147714))
HOST : 김 재 용 교수님
초 록
The world is facing global challenges such as climate changes, exploding data, emerging diseases, and cyber security. However, the CMOS technology that has posed to deal with these challenges has been challenged due to its fundamental limits in scaling, power consumptions, speed, and susceptibility to radiation. Especially, it is doubted that the CMOS technology can provide the optimized building blocks for emerging fields such as artificial intelligence. Here I propose to harness other nobs in quantum systems to tackle such challenges: spin, parity, chirality and topology. Spins and spin currents have already been used to encode and manipulate data bits in the wide range of storage devices over the past few decades. Recently, we have shown that as the spins are coupled to chiral nature of topological magnetic chiral excitations such as domain walls or skyrmions, the spin current can be much more effective in the form of chiral spin-orbit torque, exchange coupling torque, and chiral exchange drag than the conventional approach. Moreover, we find that as spins travels through chiral nanostructures such as enantiomer chiral molecules the spins become polarized due to the chiral induced spin selectivity (CISS), an intriguing phenomenon induced by relativistic spin-orbit interaction. On the other hand, as spins couple to parity, e.g. in quantum heterostructures with broken inversion symmetry like superconductor-topological matters, exotic phenomena emerge as spin-triplets, odd-parity Cooper pairing, long spin-life time, oscillatory magnetic damping, non-reciprocal transport properties, non-Abelian statistics, and Majorana zero modes. In this seminar, I will review and update the recent advances in the vibrant research on the interaction of these outstanding key players in quantum matter providing the outlook of potential applications with new functionalities based on them. In the later of talk, I will discuss the future direction and grand plans of my research.