Plasmon modes in N- layer graphene structures at zero temperature
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Plasmon modes in N‑layer graphene structures at zero temperature Phuong Dong Thi Kim1,2 · Men Nguyen Van3,4 Received: 28 February 2020 / Accepted: 6 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract We investigate the plasmon frequency and the broadening function corresponding to Landau damping in a N-MLG structure consisting of N, up to 5, MLG sheets at zero temperature. Our results present that plasmon dispersions in the system include an in-phase optical mode and N − 1 out-of-phase acoustic ones. The optical (acoustic) plasmon frequency is higher (lower) than that of MLG at the same parameters. The broadening function of plasmon dispersions is quite similar to that in case of taking into account temperature effects. In addition, the increase in separation between layers increases (decreases) acoustic (optical) plasmon frequency, making plasmon curves become identical at smaller wave vector. Besides, the imbalance in carrier density in graphene sheets affects significantly on plasmon frequencies and plasmon pattern because it separates some plasmon branches far away from the others. However, the number of plasmon branches separated from the others depends mainly on the number of layers containing different carrier density but is independent of the order of these layers in the system. Keywords Multilayer structures · Graphene · Plasmon · Collective excitations · Zero temperature
* Men Nguyen Van [email protected] Phuong Dong Thi Kim [email protected] 1
An Giang University, 18‑Ung Van Khiem Street, Long Xuyen, An Giang, Viet Nam
2
Vietnam National University, Ho Chi Minh City, Viet Nam
3
Atomic Molecular and Optical Physics Research Group, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City, Viet Nam
4
Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Viet Nam
13
Vol.:(0123456789)
Journal of Low Temperature Physics
1 Introduction Since the experimental exploration of graphene, a layer of carbon atoms arranged in honeycomb lattices, scientists have paid a lot of attention for studying this material because of its unique properties and application ability in different technology areas [1–6]. The application of Dirac’s model for theoretical calculations on graphene shows that quasiparticles in monolayer graphene (MLG) behave as chiral massless fermions with linear low energy dispersion. This character leads to a dissimilar polarization function and collective excitations in graphene, compared to those in an ordinary two-dimensional electron gas (2DEG) [5, 7–11]. Plasmon properties in graphene have been extensively studied with interesting features and meaningful applied suggestions [12–19]. Its application ability covers lots of technology fields such as optics, microscopy, nanolithography, magneto-optic data storage and catalysis [20–22]. It is evident that plasmons in multilayer structures have different characters in comparison with that in single ones because of the remarkable interaction bet
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