New understanding of the α-type band structure

Some of the polytypes in two-dimensional organic conductors, such as κ and λ, are known for the existence of dimers, whose band structure is reproduced well by use of a dimer model. We propose that α-type also has a hidden dimer structure, where the dimer-based band structure shows quite good agreement with the original ones. The dimer picture enables us to relate a with other polytypes in a unified model we proposed earlier. The deeper understanding of the characteristic structure of bands is provided which might be a help in clarifying the ground state of this polytype in the future studies.