Mode shifting due to spin polarization in single layer graphene on a substrate

Description

Graphene, an almost purely two dimensional system, has opened up new doors into modern electronics. The growing precision of optical and scattering experiments necessitates a better un- derstanding of the influence of damping on the collective mode of electrons or holes in such sheets. Further, the spin of the charge carriers is a promising candidate as an independently manipulable information carrier in electronic devices, heading towards spintronics. We report spin-sensitive partial and full linear response functions of graphene, which give access to charge- and spin-density related excitations. In contrast to two dimensional electron liquids in heterostructures, graphene’s collective mode can be strongly Landau-damped even at small wave vectors, due to single-particle interband transitions. Increasing the spin-imbalance of the free charge carriers in Dirac materials significantly broadens and shifts the plasmon. This enables to switch its lifetime (its mean free path) by tuning the spin polarization of graphene, thus, in turn, to switch the efficiency of appliances coupled to this mode. To bring our results to the test, we calculated the reflectivity of graphene on a SiO2 surface, as observed in s-wave scanning near field microscopy. The above shift in mode position affects the dipole interaction function, a key quantity of the measurement. We also predict an antiresonance in the longitudinal magnetic response, similar to that in semiconductor heterostructures.

Period	11 Sept 2018
Event title	68th Annual Meeting of the Austrian Physical Society
Event type	Conference
Location	AustriaShow on map