Magnetoplasmons of the tilted anisotropic Dirac cone materialα−(BEDT-TTF)2I3

Judit Sári, Csaba Tőke, Mark O. Goerbig
2014 Physical Review B  
We study the collective modes of a low-energy continuum model of the quasi-two-dimensional electron liquid in a layer of the organic compound α-(BEDT-TTF)_2I_3 in a perpendicular magnetic field. As testified by zero magnetic field transport experiments and ab initio theory, this material hosts both massless and massive low-energy carriers, the former being described by tilted and anisotropic Dirac cones. The polarizability of these cones is anisotropic, and two sets of magnetoplasmon modes
more » ... oplasmon modes occur between any two cyclotron resonances. We show that the tilt of the cones causes a unique intervalley damping effect: the upper hybrid mode of one cone is damped by the particle-hole continuum of the other cone in generic directions. We analyse how the presence of massive carriers affects the response of the system, and demonstrate how doping can tune α-(BEDT-TTF)_2I_3 between regimes of isotropic and anisotropic screening.
doi:10.1103/physrevb.90.155446 fatcat:2c3hj5nt7bbcdaq5f5bdyf7kee