Thermal hysteresis of Casimir suspensions enabled by vanadium dioxide

In this work, the Casimir suspensions of a nanoplate (gold or Teflon) in a liquid environment are theoretically investigated. The substrate of the system is a three-layer structure of Teflon/vanadium dioxide(VO2)/Teflon. It is found that stable suspensions of nanoplates can be achieved due to the balances of repulsive Casimir forces, gravity and buoyancy. Remarkably, the suspension positions of gold and Teflon nanoplates are strongly associated with the preceding thermal history of VO2, i.e., heating or cooling. The differences in the suspension positions between the heating and cooling can reach tens of nanometers. Finally, a thermal hysteresis of Casimir suspensions via the temperature is shown for gold and Teflon nanoplates. Our findings offer the possibility of designing conceptually new devices in micro and nanoelectromechanical systems (MEMS and NEMS).