Low integer Landau level filling factors ν and indications for the fractional ν=1/2 in the 2D organic metal κ-(BEDT-TTF)2I3

In the two-dimensional (2D) organic metal κ-(BEDT-TTF)2I3 the low integer Landau level filling factors ν=1-4 are observed under specific experimental conditions. In high magnetic fields even the presence of the fractional ν=1/2 is strongly indicated in this multilayer material. These ν are detected by the chemical potential μ, i.e. a thermodynamic quantity, which could be probed under complex fermiological conditions.