Pressure-induced quenching of soliton in the pernigraniline-base polymer

An n-type soliton of the pernigraniline-base polymer under pressure was investigated in an extended Ginder–Epstein model. The results showed that: while increasing pressure up to 5.69 GPa, excitation energy for a soliton reduced from 10.02 to 3.64 eV, meanwhile the gap and the lattice distortion disappeared. Original band changed from style of a semiconductor to that of a metal. The results agree with the experimental observations that electrical conductivity is increasing with applied pressure until a saturated value. Our theory supports soliton-conduction mechanism for the polymer under pressures less than 5.69 GPa. Under higher pressure, carriers would be electrons as if in a metal.