Magnetic susceptibility and electrical conductivity of Perylene radical cation salts

Abstract

PACS. 71.30.+h Metal-insulator transitions and other electronic transitions - 72.80.Le Polymers; organic compound (including organic semiconductors),

Temperature dependence of the intrastack exchange interaction for a quasi-one-dimensional organic conductor

“…A decreasing wave-function overlap for increasing temperature resulting in contraction of the conduction-electron bandwidth and corresponding increase of the conduction-electron magnetic susceptibility has been suggested, based on experimental evidence, for perylene radical cation salts in the past. 17 This variation has now been unraveled quantitatively.…”

“…We suggested from NMR investigations that such an interstack coupling proceeds via bonding contribution between the H atoms of the pyrene molecules and the F atoms of the hexafluoride anions. 6,17 As long as pyrene molecules or anions are in motion this coupling cannot be established. This is the scenario for TϾT p in the fluctuating regime.…”

Temperature dependence of intra-stack defect spin–conduction-electron spin interaction in fluoranthene and perylene radical cation salts

“…Together with the above-mentioned NMR measurements of the longitudinal relaxation rate of the arene protons and the counter-ion 19 F nuclei [11,12], these results indicate the following conclusions. For the locking-in of a Peierls distortion of the crystal lattice, a coupling of the CDWs in neighbouring stacks is a necessary precondition [13]. This inter-stack coupling can be established via the counter-ions, which are located between the stacks.…”

Anisotropy of charge and spin motion in perylene hexafluoroarsenate salts

“…We mainly discuss results derived for one selected crystal, sample 'A', characterized in table 1. Microwave conductivity was determined at 10.15 GHz for σ and 10.3 GHz for σ ⊥ using the cavity perturbation method [5,13]. Figure 2 shows the results for sample A on a logarithmic scale.…”

“…The perylene (PE) hexafluoroarsenate salt was selected for the present investigation [4,6,[11][12][13][14][15][16]. It has an unusually wide temperature separation between the (second order) structural phase transition at T s ≈ 171 K, where the arrangement of the perylene molecules perpendicular to the stacks is modified [12], and the subsequent Peierls transition at T P ≈ 102 K, where the conductivity decrease is more pronounced (figure 2) and a static energy gap is opened at the Fermi level [4,13]. The main disadvantage of this sample choice is the somewhat complicated crystal structure (figure 1) with neutral PE molecules surrounding the conducting stacks, i.e.…”