Refrigeration in 2D: Electrostaticaloric effect in monolayer materials

Abstract

As electrical device components are scaled down to atomic sizes, management of waste heat becomes a major issue in device performance. Minimizing energy consumption of electrical components and waste heat generation are critical issues in the operation of such devices. Interest in alternative cooling mechanisms, such as those provided by electrocaloric, magnetocaloric, elastocaloric, and thermoelectric materials, may also be necessary in mitigating issues associated with waste heat generation. In this work, we provide theoretical predictions for an alternative cooling mechanism, accomplished by utilizing electrostatic gating to induce structural phase transitions in monolayer materials. We refer to this mechanism as the electrostaticaloric effect in reference to the mechanism of electrostatic doping that drives the structural phase transformation and entropy change in the material. Recent predictions and experimental observation that electrostatic gating can induce structural phase transformations in monolayer materials opens the possibility for new application areas. Here, we explore the potential for electrostatically induced structural phase transformations in monolayer ${\mathrm{MoTe}}_{2}$ to be used in a Carnot refrigeration cycle. We predict that a temperature change of 10--15 K may be possible in devices that utilize monolayer ${\mathrm{MoTe}}_{2}$ as the active phase change material. This mechanism may prove useful for future electrical devices which require cooling at the component level, and for which small monolayer devices are necessary.