Thermal resistance, controlled by means of electrical pulses

Controlling the heat flow is key to enhance the performance in a wide variety of systems. In electronic devices, such as mobile phones or any type of processor, overheating decreases their performance and reduces their lifetime.  All these technologies are based on materials with a certain resistance to the heat flow through them. This thermal resistance can be modulated by applying the appropiate voltage. This is the main result reached by Center for Research in Biological Chemistry and Molecular Materials (CiQUS) researchers in a new study recently published in ACS Applied Materials & Interfaces journal. Led by Rafael Ramos and Francisco Rivadulla, this work paves the way for the design of thermal regulators and more efficient and sustainable technologies.

The development of new functional materials with tunable thermal conductivity offers solutions to challenges such as heat dissipation in electronic components. Among these devices of interest are memristors (acronym derived from memory resistor), a component with resistive switching effect: when an electric field is applied, the material can reversibly alternate between different levels of electrical resistance. In the new study, researchers have shown that alongside electrical resistive switching, a thermal resistive switching effect also occurs at the metal-oxide interface of the material, due to the accumulation of oxygen ions. This alteration in heat flow resistance can be modulated by around 20% at room temperature.

"Oxides are materials with thermal resistance highly sensitive to oxygen concentration, so by inducing a displacement of these ions when an electric field is applied, we modify their thermal properties," explains Víctor Álvarez, a PhD candidate at CiQUS and the study's lead author. "Depending on the resistive state of the device, we've achieved a reversible increase or decrease in thermal conductivity with an electric field." The research is part of the MEMTHERM project, funded through grants for Strategic Projects Oriented towards Ecological and Digital Transition from the Ministry of Science and Innovation (Spain). It aims to develop new thermoregulators based on controlling ion movement in dielectric oxides.