2021/08/17 by Debasmita Giri, Arijit Kundu, Giri, Debasmita +1
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Graphene research and applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2108.07782
openalex publication_date 2021/08/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the collective charge-density modes (plasmons) of two-dimensional nonsymmorphic Dirac semimetals, within the random-phase approximation (RPA) in presence of Coulomb interaction. Without loss of generality, we consider a system in a two-dimensional square-lattice, based on the model originally predicted by Young and Kane (https://doi.org/10.1103/PhysRevLett.115.126803), where the non-interacting band-structure consists of three band-touching points, near which the electronic states follow Dirac equations. Two of these Dirac nodes, at the momentum points X1 and X2, are anisotropic, i.e., disperse with different velocities in different directions, whereas the third Dirac point at M is isotropic. Interestingly we find that the system of these three Dirac nodes hold a single low-energy plasmon mode, within its particle-hole gap, that disperses in isotropic manner, in the case when the nodes at X1 and X2 are related by symmetry, which we further show in a long-wavelength approximation. We also discuss the effects of possible perturbations that can give rise to anisotropic plasmon dispersions. Our results suggest, in similarity with graphene, plasmon modes of such non-symmorphic semimetals are highly tunable and hold promise for possible applications.