Seon Namgung - UNIST

Wednesday 18 Feb 2026, 08:30 → 19:45 US/Eastern

IAMM

https://physics.unist.ac.kr/members/%EB%82%A8%EA%B6%81%EC%84%A0/

09:00 → 10:00 Arrive at IAMM with host: Joon Sue Lee

Travel to IAMM.

Speaker: Joon Sue Lee (University of Tennessee, Knoxville)

10:00 → 10:20 Talk Prep

10:20 → 11:20 Seminar: Dr. Seon Namgung (UNIST)

Title: Transport Phenomena in Chiral Tellurium: Chirality-Induced Spin Selectivity and Nonlinear Hall Effect

Abstract: The chirality-induced spin selectivity (CISS) effect, where chiral materials preferentially transmit electrons of a particular spin, has sparked intense interest through its scientific implications and spintronic applications such as giant magnetoresistance, anomalous Hall effect, selective enantiomer adsorption on a magnetic substrate, and enhanced electrocatalytic activity via spin polarization. Despite extensive research, its underlying mechanism is not clearly revealed yet. Even though the spatial distribution of spin polarization in chiral systems is one of the key clues to reveal the spin scattering mechanism in CISS, it has remained experimentally elusive. In this talk, CISS-based spin polarization induced by an electric current in nonmagnetic chiral tellurium nanowires will be demonstrated, which is probed by spatially resolved reflective magnetic circular dichroism measurements. The observed spin polarization scales linearly with current amplitude, aligns parallel to the current direction, reverses with chirality or current flow, indicative of CISS. Furthermore, the current-induced spin polarization exhibits identical signs in both the nanowire and electrodes, contrary to the presumed spin filter scenario so far. In addition, the spin relaxation lengths on graphene electrodes are measured to be several micrometers, in good agreement with previously reported values measured by electrical means such as spin valves. This work establishes a new paradigm for investigating spin-dependent phenomena in chiral materials and opens avenues for developing chirality-based spintronic and quantum devices. In addition, nonlinear Hall effect of Te will be presented, which is connected to the Berry curvature dipole of the inversion symmetry broken Te system.

Reference
Real Space Imaging of Spin Scattering in Chirality-Induced Spin Selectivity, ACS Nano 2025, 19, 42046−42055 (https://pubs.acs.org/doi/10.1021/acsnano.5c10577)

Speaker: Seon Namgung

11:30 → 12:00 Research Meeting

Speaker: Ruixing Zhang (Department of Physics and Astronomy, University of Tennessee Knoxville)

12:00 → 14:30 Lunch

14:30 → 15:00 Research Meeting

15:00 → 15:30 Research Meeting

15:30 → 16:00 Research Meeting

16:00 → 16:30 Research Meeting

Speaker: Wonhee Ko (University of Tennessee, Knoxville)

16:30 → 17:00 Research Meeting

18:00 → 19:30 Dinner