First-Principles Study of Electronic Structure in α-(BEDT-TTF)₂I₃at Ambient Pressure and with Uniaxial Strain

Within the framework of the density functional theory, we calculate the electronic structure of α-(BEDT-TTF)₂I₃ at 8K and room temperature at ambient pressure and with uniaxial strain along the a- and b-axes. We confirm the existence of anisotropic Dirac cone dispersion near the chemical potential. We also extract the orthogonal tight-binding parameters to analyze physical properties. An investigation of the electronic structure near the chemical potential clarifies that effects of uniaxial strain along the a-axis is different from that along the b-axis. The carrier densities show T² dependence at low temperatures, which may explain the experimental findings not only qualitatively but also quantitatively.