Origin of Hopping Dynamics in Hexatic Smectic B and Smectic A Liquid Crystals

Origin of hopping dynamics in liquid crystals is investigated by constant-pressure and constant-temperature molecular dynamics simulations. Hopping dynamics is observed in both hexatic smectic B (HexB) and smectic A (SmA) liquid crystals, however in different directions. At the crystal-Hex B transition, a second order transtition occurs where the layer thickness increases continuously. At the HexB-SmA transition, melting inside the layers is observed. The hopping occurs in the direction normal to the direction with loose density, i.e., xy-direction in HexB and z-direction in SmA.