what if the future brought computers that worked on heat currents instead of electricity? how about those massive data centers capturing waste heat now at the data center outflow but rather at the micro chip level? that is all part of what is possible from the ground breaking work recently published by tom ruokola in the department of applied physics at aalto university.

new mechanisms for controlling heat flow and for converting heat to work in small-scale solid-state systesm are always being pursued: whether through using convection cooling or liquid cooling. when you factor in the ever increasing need for miniaturization leading to higher power densities, the need rises further. ruokola designed two so called mesoscopic structures for heat transport. the structures are based on single-electron phenomena: the movement of single electrons through the constructed system. the electrons carry an arbitrary amount of heat in addition to their electrical charged. the discovery required new ideas and methods for heat transfer, since the smaller the scale of devices and components become, the more quantum level phenomena come into play.

together with researcher teemu ojanen of o.v. lounasmaa laboratory in aalto university, ruokola developed a single-electron diode, a rectifier, which allows heat to flow only in one direction and blocks the flow to the other. the idea comes from the well-known electronic component of a similar function.

in the study, they consider two type of mesoscopic heat transport devices, namely heat rectifiers and heat engines. as many of coolingzone readers know, a rectifier is a device which allows heat to flow in one direction but flow in the other direction is suppressed. two different rectifiers are proposed: one is a nonlinear oscillator controlling photonic heat flow in a microwave circuit, the other is a pair coulomb blockade islands rectifying electronic heat currents. particularly the latter device offers rectification performance unparalleled in the literature.

the researchers also propose a new class of thermoelectric heat engines where electronics are transported between two reservoirs but heat is exchanged betweet the transport system and a third rervoide by microwave photons. heat and charge flows are therefore separated, offering much greater flexibility than usual thermoelectrics. the full study, 60 pages in all, can be downloaded from coolingzone at this link: "thermal transport in mesoscopic devices"