Tilt-induced kink in the plasmon dispersion of two-dimensional Dirac electrons

Abstract

The list of two dimensional Dirac systems with a tilt in their Dirac cone spectrum is expanding, and now in addition to organic system $\alpha$(BEDT-TTF)${}_2$I${}_3$ includes the two dimensional $8Pmmn$-borophene sheet, which allows for controlled doping by the gate voltage. We analytically calculate the polarization function of tilted Dirac cone for arbitrary tilt parameter, $0\le \eta <1$, and arbitrary doping. This enables us to find two interesting plasmonic effects solely caused by the tilt: (i) In addition to the standard plasmon oscillations, strong enough tilt, induces an additional linearly dispersing overdamped branch of plasmons, which is strongly Landau damped due to overlap with a large density of intra-band free particle-hole (PH) excitations. (ii) There appears a kink in the plasmon dispersion for any non-zero tilt parameter. The kink appears when the plasmon branch enters the inter-band continuum of PH excitations. This kink becomes most manifest for wave vectors perpendicular to the tilt direction and fades away by approaching the tilt direction. Experimental measurement of the wave vector and energy of the plasmonic kink, when combined with our analytic formula for the kink energy scale, allows for a direct experimental measurement of the tilt parameter.

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References in corpus (19)

• Electric Field Effect in Atomically Thin Carbon Films
• The electronic properties of graphene
• Weyl and Dirac Semimetals in Three Dimensional Solids
• Dielectric function, screening, and plasmons in 2D graphene
• Dynamical polarization of graphene at finite doping
• Dirac materials
• Dirac fermions in borophene
• Tilted anisotropic Dirac cones in quinoid-type graphene and alpha-(BEDT-TTF)_2I_3
• Electronic properties of 8-Pmmn borophene
• Transport Properties and Diamagnetism of Dirac Electrons in Bismuth
• Strain-induced pseudomagnetic field in Dirac semimetal borophene
• Effect of electron-hole asymmetry on optical conductivity in 8-Pmmn borophene
• Possible Verification of Tilted Anisotropic Dirac Cone in α-(BEDT-TTF)_2 I_3 Using Interlayer Magnetoresistance
• Anisotropic plasmons, Friedel oscillations and dynamical screening in $8-Pmmn$ borophene
• Electronic Properties Close to Dirac Cone in Two-Dimensional Organic Conductor $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Magnetoplasmons of the tilted-anisotropic Dirac cone material $\alpha -$(BEDT-TTF)${}_2$I${}_3$
• Disorder in tilted Weyl semimetals from a renormalization group perspective
• Electromagnetic modes from Stoner enhancement
• Structural and electronic properties of $\alpha ,\beta$-(BEDT-TTF)${}_2$I${}_3$ and $\kappa$-(BEDT-TTF)${}_2$X${}_3$ (X=I,F,Br,Cl) organic charge transfer salts

Cited by in corpus (24)

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• Kinky plasmons in double layers of borophene-borophene and borophene-graphene
• Anisotropic effects in two-dimensional materials
• Polarization tensor for tilted Dirac fermion materials: Covariance in deformed Minkowski spacetime
• Synthetic non-Abelian gauge fields and gravitomagnetic effects in tilted Dirac cone systems
• Electrodynamics of tilted Dirac/Weyl materials: A unique platform for unusual surface plasmon polaritons
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• Signatures of Lifshitz transition in the optical conductivity of two-dimensional tilted Dirac materials
• Perpendicular Andreev reflection: Solid state signature of black hole horizon
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• Plasmons in anisotropic Dirac systems
• Undamped transverse electric mode in undoped two-dimensional tilted Dirac cone materials
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• Mapping borophene onto graphene: Quasi-exact solutions for guiding potentials in tilted Dirac cones
• Polarizability, plasmons, and screening in 1T${}^{\prime }$-MoS${}_2$ with tilted Dirac bands
• Electronic properties of the Dirac and Weyl systems with first- and higher-order dispersion in non-Fermi-liquid picture
• Equations of macroscopic electrodynamics for two-dimensional crystals
• Singular low-energy states of tilted Dirac semimetals induced by the fermion-fermion interactions
• Designer gapped and tilted Dirac cones in lateral graphene superlattices
• Collective light-matter interaction in plasmonic waveguide quantum electrodynamics
• Critical fates induced by the interaction competition in three-dimensional tilted Dirac semimetals