arXiv subjects

Benjamin I. Weintrub

Publications and source records attributed to Benjamin I. Weintrub.

2 recordsLinked to original sources

arXiv2022

High power density energy harvesting devices based on the anomalous Nernst effect of Co/Pt magnetic multilayers

The anomalous Nernst effect (ANE) is a thermomagnetic phenomenon with potential applications in thermal energy harvesting. While many recent works studied the approaches to increase the ANE coefficient of materials, relatively little effort was devoted to increasing the power supplied by the effect. Here we demonstrate a nanofabricated device with record power density generated by the ANE. To accomplish this, we fabricate micrometer-sized devices in which the thermal gradient is three orders of magnitude higher than conventional macroscopic devices. In addition, we use Co/Pt multilayers, a system characterized by a high ANE thermopower (~1 microV/K), low electrical resistivity, and perpendicular magnetic anisotropy. These innovations allow us to obtain power densities of around 13 W/cm3. We believe that this design may find uses in harvesting wasted energy in e.g. electronic devices.

cond-mat.mtrl-sci↗

arXiv2022

Generating extreme electric fields in 2D materials by dual ionic gating

We demonstrate a new type of dual gate transistor to induce record electric fields through two-dimensional materials (2DMs). At the heart of this device is a 2DM suspended between two volumes of ionic liquid (IL) with independently controlled potentials. The potential difference between the ILs falls across an ultrathin layer consisting of the 2DM and the electrical double layers above and below it, thereby producing an intense electric field across the 2DM. We determine the field strength via i) electrical transport measurements and ii) direct measurements of electrochemical potentials of the ILs using semiconducting 2DM, WSe2. The field strength across the material reaches more than 3.5 V/nm, the largest static electric field through any electronic device to date. We demonstrate that this field is strong enough to close the bandgap of trilayer WSe2 driving a semiconductor-to-metal transition. Our approach grants access to previously-inaccessible phenomena occurring in ultrastrong electric fields.

physics.app-ph↗