Using surface plasmonics to turn on fullerene's dark excitons

Scientific paper - Original scientific paper

• Author: Vito Despoja
• Author: D. J. Mowbray
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

Using our recently proposed Bethe-Salpeter G_0W_0 formulation, we explore the optical absorption spectra of fullerene (C_60) near coinage metal surfaces (Cu, Ag, and Au). We pay special attention to how the surface plasmon ω_S influences the optical activity of fullerene. We find that the lower-energy fullerene excitons at 3.77 and 4.8 eV only weakly interact with the surface plasmon. However, we find that the surface plasmon strongly interacts with the most intense fullerene π exciton, i.e., the dipolar mode at ℏω+≈6.5 eV, and the quadrupolar mode at ℏω−≈6.8 eV. When fullerene is close to a copper surface (z_0≈5.3 Å), the dipolar mode ω_+ and “localized” surface plasmons in the molecule/surface interface hybridize to form two coupled modes which both absorb light. As a result, the molecule gains an additional optically active mode. Moreover, in resonance, when ω_S≈ω_±, the strong interaction with the surface plasmon destroys the ω− quadrupolar character and it becomes an optically active mode. In this case, the molecule gains two additional very intense optically active modes. Further, we find that this resonance condition, ω_S≈ω_±, is satisfied by silver and gold metal surfaces.

• Keywords (english): fullerene; optical absorption; GW-BSE; surface plasmons
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical review B: Condensed matter and materials physics
• Numbering: vol. 89, no. 19, 195433
• p-ISSN: 1098-0121
• e-ISSN: 1550-235X
• DOI: https://doi.org/10.1103/PhysRevB.89.195433
• URN:NBN: urn:nbn:hr:217:807103
• Publication: 2014
• Document URL: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.195433
• Type of resource: Text
• Access conditions: Open access
• Public note: Copyright (2014) by the American Physical Society. Received 17 February 2014; revised manuscript received 9 April 2014; published 21 May 2014.
• Created on: 2019-11-30 21:05:58