Cyclotron resonance in the organic metal α-(BEDT-TTF)2TlHg(SCN)4

Cyclotron resonance studies of the density-wave state of the organic metal α-(BEDT-TTF)2TlHg(SCN)4 have been carried out in the frequency range 50–100 GHz. Two strong resonances were observed, corresponding to cyclotron masses 1.35me and 0.5me. Quantum oscillations were also observed in the electrodynamic response at high magnetic fields; their frequency is very similar to that of the Shubnikov-de Haas oscillations seen in low frequency transport studies.