Extended Data Fig. 4: Investigations of transport mechanisms in PBFDO.

a,b, ESR spectroscopy of PBFDO at different temperatures. The ESR intensities of the PBFDO solid slightly increased with elevating temperature from 140 to 260 K (a), which was considered as a signature of open-shell diradical resonance⁵⁴. Another phenomenon of line broadening of the ESR signal was observed above 298 K, implying the existence of conduction electrons, which is a typical signature in CPs^25,42 (b). These conduction electrons are increasingly scattered by phonons with increasing temperature, resulting in a shortening of the spin-lattice relaxation time and, hence, a decrease in conductivity and broadening of the ESR signals above 298 K (ref. ⁵⁵). c, The total electromagnetic-wave shielding percentage versus frequency. d, Electromagnetic-interference shielding efficiency (EMI SE) of PBFDO. SEr represents shielding efficiency from reflection and SEa represents that from absorption. The outstanding SE of PBFDO can be considered as another characteristic of metallic state. e,f, Temperature dependence of phase coherence time, τ_φ (e), and coherence length, L_φ (f), extracted from MC. Inelastic scattering would interfere with the coherence of delocalized charge wave, especially when the L_φ is comparable with the magnetic length, L_B = (ħ/eB)^1/2 ≈ 25.66 B^−1/2 nm (ref. ⁵⁶). g,h, The conductivity of PBFDO film under the applied magnetic field B = 5 T (g) (the values were corrected using the conductivity under B = −5 T to eliminate the deviation caused by the Hall effect; the error bar represents the standard deviation caused by the uncertainty of film thickness) and corresponding log–log plot of W versus temperature (h). The zero-field conductivity was also measured for the same sample, exhibiting the characteristic of critical region, thus eliminating the deviations between different samples.