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Unconventional Optical Response in Engineered Au-Ag Nanostructures

preprint
submitted on 06.06.2019 and posted on 07.06.2019 by Dev Kumar Thapa, Subham Kumar Saha, Guru Pratheep Rajasekar, Biswajit Bhattacharyya, Rekha Mahadevu, Anshu Pandey
This article describes the optical properties of nanostructures composed of silver particles embedded into a gold matrix. In previous studies these materials were shown to exhibit temperature dependent transitions to a highly conductive and strongly diamagnetic state. Here we describe the anomalous optical properties of these nanostructures. Most notably, these materials fail to obey Mie theory and exhibit an unconventional resonance with a maximum at about 4 eV, while the usual gold and silver localized surface plasmon resonances are suppressed. This effect implies a significant deviation from the bulk dielectric functions of gold and silver. We further resolved this resonance into its absorbance and scattering sub-parts. It is observed that the resonance is largely comprised of scattering, with negligible losses even at ultraviolet frequencies.

Funding

DST Nanomission grant (SR/NM/NS-1117/2012)

DST SERB IRHPA grant (IR/S2/PU-0005/2012)

History

Email Address of Submitting Author

anshup@iisc.ac.in

Institution

Indian Institute of Science

Country

India

ORCID For Submitting Author

0000-0003-3195-1522

Declaration of Conflict of Interest

There is no Conflict of Interest

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