Acoustic plasmonics of Au grating/Bi2Se3 thin film/sapphire hybrid structures
Acoustic plasmonics of Au grating/Bi2Se3 thin film/sapphire hybrid structures作者机构：Physikalisches InstitutUniversitat StuttgartPfaffenwaldring 5770550 StuttgartGermany State Key Laboratory for Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing 100871China Physics Institute ⅡUniversity of Cologne50937 KolnGermany Physikalisches Institut der Universitat Wurzburg97074 WurzburgGermany Institute for Topological Insulators97074 WurzburgGermany
出 版 物：《Chinese Physics B》 (中国物理B（英文版）)
年 卷 期：2020年第29卷第6期
页 面：49-53页
核心收录：
学科分类：07[理学] 070205[理学-凝聚态物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 0704[理学-天文学] 0702[理学-物理学]
主 题：surface plasmon polaritons topological insulator infrared optoelectronics nanophotonics
摘 要：The surface plasmon polaritons of the topological insulator Bi2Se3 can be excited by using etched grating or grave structures to compensate the wave vector mismatch of the incident photon and plasmon. Here, we demonstrate novel gold grating/Bi2Se3 thin film/sapphire hybrid structures, which allow the excitation of surface plasmon polaritons propagating through nondestructive Bi2Se3 thin film with the help of gold diffractive gratings. Utilizing periodic Au surface structures,the momentum can be matched and the normal-incidence infrared reflectance spectra exhibit pronounced dips. When the width of the gold grating W(with a periodicity 2 W) increases from 400 nm to 1500 nm, the resonant frequencies are tuned from about 7000 cm-1 to 2500 cm-1. In contrast to the expected ■ dispersion for both massive and massless fermions,where q ~π/W is the wave vector, we observe a sound-like linear dispersion even at room temperature. This surface plasmon polaritons with linear dispersion are attributed to the unique noninvasive fabrication method and high mobility of topological surface electrons. This novel structure provides a promising application of Dirac plasmonics.
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