1. Do Thi Bich Hue, Wen Jun Ding, Jeremy Zhen Jie Lim, Xiao Xiong, Ching Eng Png, Michel Bosman, Lay Kee Ang, and Lin Wu, “Particle simulation of plasmons”, 47th IEEE International Conference on Plasma Science (ICOPS2020), Singapore, 6-10 December 2020.
Classical macroscopic electromagnetic descriptions fail to accurately predict the optical response of plasmonic nanostructures approaching nanometer length scales due to the omission of nonlocality and free electron spill-out. Alternatively, microscopic first-principles approaches are accurate, yet too
computationally intensive for multiscale problems. Starting from a microscopic viewpoint but more computationally efficient, particle-in-cell (PIC) simulation provides an appropriate mesoscopic treatment for such problems. Here, we leverage on the inherent soft boundary conditions of PIC to study the spill-out effects of surface electrons in mesoscopic-scale metal nanostructures, specifically Na nanowires. The relationship between the surface plasmon resonance frequency and the radius of the nanowire is investigated, exhibiting a 1/R redshift, which agrees well with the selfconsistent hydrodynamic method that includes spill-out of electron density. The developed methodology can be extended to model noble metals by including inter-band transitions, di-metallic nanoplasmonic structures, electron spill-out and charge transport between nearly touching nanoparticles.
A*STAR SERC Young Individual Research Grants (YIRG No. A1784c0020), the National Research Foundation Singapore (NRF2017-NRF NSFC002-015 and NRF2016-NRFANR002). the MOE T2 grant (2018-T2-1-007), USA ONRG grant (N62909-19-1-2047) and MOE PhD RSS. the Singapore Ministry of Educationʼs Academic Research Fund Tier 1 (R-284-000- 179-133).