Cyclotron radiation and emission in graphene

Peculiarity in the cyclotron radiation and emission in graphene is theoretically examined in terms of the optical conductivity and relaxation rates to propose that graphene in magnetic fields can be a candidate for realizing the Landau-level laser, proposed decades ago [H. Aoki, Appl. Phys. Lett. 48, 559 (1986)].

Figure 1

(Color online) Cyclotron absorption (green) and emission (red) processes schematically depicted for the ordinary (a) and graphene (b) quantum Hall systems. Black lines represent the band dispersion, while blue lines the Landau levels.

Figure 2

A typical density of states for graphene for an intermediate disorder ($\Gamma /{\omega }_c=0.25$ here).

Figure 3

(Color online) Optical conductivity against $\omega$ is shown for temperatures $k_{B}T/\hslash {\omega }_c=0–2.0$ for a fixed value of $\Gamma /\hslash {\omega }_c=0.25$ with ${\epsilon }_F=0$.