title: Ultraviolet and visible range plasmonics in the topological insulator Bi1.5Sb0.5Te1.8Se1.2.
abstract: The development of metamaterials, data processing circuits and sensors for the visible and ultraviolet parts of the spectrum is hampered by the lack of low-loss media supporting plasmonic excitations. This has driven the intense search for plasmonic materials beyond noble metals. Here we show that the semiconductor Bi1.5Sb0.5Te1.8Se1.2, also known as a topological insulator, is also a good plasmonic material in the blue-ultraviolet range, in addition to the already-investigated terahertz frequency range. Metamaterials fabricated from Bi1.5Sb0.5Te1.8Se1.2 show plasmonic resonances from 350 to 550 nm, while surface gratings exhibit cathodoluminescent peaks from 230 to 1,050 nm. The observed plasmonic response is attributed to the combination of bulk charge carriers from interband transitions and surface charge carriers of the topological insulator. The importance of our result is in the identification of new mechanisms of negative permittivity in semiconductors where visible range plasmonics can be directly integrated with electronics.
authors.affiliation: Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Jun-Yu
authors.initials: JY
authors.lastname: Ou
authors.affiliation: Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Jin-Kyu
authors.initials: JK
authors.lastname: So
authors.affiliation: Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Adamo
authors.affiliation: School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Azat
authors.initials: A
authors.lastname: Sulaev
authors.affiliation: 1] School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore [2] RMIT University, School of Applied Sciences, Department of Physics, VIC 3000, Australia.
authors.forename: Lan
authors.initials: L
authors.lastname: Wang
authors.affiliation: 1] Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ, UK [2] Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Nikolay I
authors.initials: NI
authors.lastname: Zheludev