Metal-insulator transition in iron doped 2H-TaSe2: Suggestion of chiral unitary localization

We investigated the conduction of electrons in a quasi two-dimensional random magnetic field (RMF) system, namely iron-doped transition metal dichalcogenide 2H-FexTa1-xSe2. We observed a clear metal-insulator transition by increasing the Fe doping rate. The temperature dependence of the resistances is consistent with the unitary class of Anderson localization. However, the observed critical sheet resistance is between 2 and 19 k Omega, which is inconsistent with the unitary class (2h/e(2) = 51.6 k Omega). We propose that chiral symmetry can be present in 2H-FexTa1-xSe2 because the magnetoresistance of the crystals is similar to that of dirty graphites. (C) 2014 Elsevier B.V. All rights reserved.