Plasmonic Dirac Cone in Twisted Bilayer Graphene

Brey, L. ; Stauber, T. ; Slipchenko, T. ; Martín-Moreno, L. (Universidad de Zaragoza)

Resumen: We discuss plasmons of biased twisted bilayer graphene when the Fermi level lies inside the gap. The collective excitations are a network of chiral edge plasmons (CEP) entirely composed of excitations in the topological electronic edge states that appear at the AB-BA interfaces. The CEP form a hexagonal network with a unique energy scale ?p=(e2)/(?0?t0) with t0 the moiré lattice constant and ? the dielectric constant. From the dielectric matrix we obtain the plasmon spectra that has two main characteristics: (i) a diverging density of states at zero energy, and (ii) the presence of a plasmonic Dirac cone at â., ?~?p/2 with sound velocity vD=0.0075c, which is formed by zigzag and armchair current oscillations. A network model reveals that the antisymmetry of the plasmon bands implies that CEP scatter at the hexagon vertices maximally in the deflected chiral outgoing directions, with a current ratio of 4/9 into each of the deflected directions and 1/9 into the forward one. We show that scanning near-field microscopy should be able to observe the predicted plasmonic Dirac cone and its broken symmetry phases.

Idioma: Inglés

DOI: 10.1103/PhysRevLett.125.256804

Año: 2020

Publicado en: Physical Review Letters 125, 25 (2020), 256804 [6 pp]
ISSN: 0031-9007

Originalmente disponible en: Texto completo de la revista

Factor impacto JCR: 9.161 (2020)

Categ. JCR: PHYSICS, MULTIDISCIPLINARY rank: 7 / 84 = 0.083 (2020) - Q1 - T1

Factor impacto SCIMAGO: 3.688 - Physics and Astronomy (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/Q-MAD
Financiación: info:eu-repo/grantAgreement/EC/H2020/785219/EU/Graphene Flagship Core Project 2/GrapheneCore2
Financiación: info:eu-repo/grantAgreement/EC/H2020/881603/EU/Graphene Flagship Core Project 3/GrapheneCore3
Financiación: info:eu-repo/grantAgreement/ES/MINECO/FIS2017-82260-P
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2017-88358-C3-1-R
Financiación: info:eu-repo/grantAgreement/ES/MINECO/PGC2018-096955-B-C42
Financiación: info:eu-repo/grantAgreement/ES/MINECO/PGC2018-097018-B-100

Tipo y forma: Article (Published version)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)