Magneto-optical and magneto-transport studies of electron- electron interactions in organic conductors using fields up to 50T

Abstract

This paper reviews our recent studies of charge-transfer salts of the ion bis(ethylenedithio)tetrathiafulvalene (ET). The first part describes magneto-transport measurements which demonstrate modifications of the band structures of (ET) 2KHg(SCN) 4 and β-(ET) 2AuBr 2 due to antiferromagnetic order; the antiferromagnetism is probably caused by the presence of spin-density waves. The second part reports cyclotron resonance studies of (ET) 2KHg(SCN) 4, (ET) 2NH 4Hg(SCN) 4 and (ET) 2Cu(SCN) 2, which reveal effective masses between 0.4 m e and 1.2 m e. In contrast, magneto-transport measurements reveal masses between 2.0 m e and 3.5 m e. The difference between the results is thought to indicate the strength of electron-electron interactions in these materials.