Amplitudon and phason modes of electrocaloric energy interconversion

Solid-state electrothermal energy interconversion utilising the electrocaloric effect is currently being considered as a viable source of applications alternative to contemporary cooling and heating technologies. Electrocaloric performance of a dielectric system is critically dependent on the number of uncorrelated polar states, or 'entropy channels' present within the system phase space. Exact physical origins of these states are currently unclear and practical methodologies for controlling their number and creating additional ones are not firmly established. Here we employ a multiscale computational approach to investigate the electrocaloric response of an artificial layered-oxide material that exhibits Goldstone-like polar excitations. We demonstrate that in the low-electric-field poling regime, the number of independent polar states in this system is proportional to the number of grown layers, and that the resulting electrocaloric properties are tuneable in the whole range of temperatures below T_C by application of electric fields and elastic strain.