An order parameter with broken polarization symmetry is proposed for the pressure-induced molecular dissociation transitions in nitrogen. The experimental dissociative transition pressure dependence of the calculated order parameter is well described by a power law of the form P=kq2. Our results unveil the important role of symmetry breaking in nitrogen under high pressure and further demonstrate a path from dense molecular fluid to fully polymeric phases by breaking local polarization reversal symmetry.
Categories: cond-mat.mtrl-sci cond-mat.stat-mech