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Physics Colloquium: Binghai Yan

March 25 | 4:00 pm - 5:00 pm

Title: Topology, Spin and Orbital in DNA-like Chiral Quantum Materials

Abstract: In chemistry and biochemistry, chirality represents the structural asymmetry characterized by non-superimposable mirror images for a material like DNA. In physics, however, chirality commonly refers to the spin-momentum locking of a particle or quasiparticle in the momentum space. While seemingly unrelated characters in different fields, the structural chirality leads to the electronic chirality featured by the orbital-momentum locking encoded in the wavefunction of chiral molecules or solids, i.e. the chirality information transfers from the atomic geometry to the electronic orbital. The electronic chirality provides deep insights into the chirality-induced spin selectivity (CISS), in which electrons exhibit salient spin polarization after going through a chiral material. It also gives rise to new phenomena, such as anomalous circularly polarized light emission (ACPLE), in which the light handedness relies on the emission direction. These chirality-driven effects will generate broad impacts in fundamental science and technology applications in spintronics, optoelectronics, and biochemistry.

References:[1] Y Liu, J Xiao, J Koo, B Yan, Chirality-driven topological electronic structure of DNA-like
materials, Nature Materials 20 (5), 638 (2021). [2] Y. Adhikari, et al, Interplay of Structure Chirality, Electron Spin and Topological Orbital in Chiral Molecular Spin Valves, Nature Comm, 14, 5163 (2023). [3] L. Wan, Y. Liu, M.J. Fuchter, B. Yan, Anomalous circularly polarized light emission in organic light-emitting diodes caused by orbital–momentum locking, Nature Photonics 17, 193 (2023).

Host: Dali Sun 

Details

Date:
March 25
Time:
4:00 pm - 5:00 pm
Event Category:

Organizer

Dali Sun

Venue

Riddick 301
2401 Stinson Drive
Raleigh, NC 27695 United States
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