Converting Waste Heat to Electricity in Microelectronics using Spintronic Thermopower
Project name: CONVERT - Converting Waste Heat to Electricity in Microelectronics using Spintronic Thermopower
Project duration: 12/2022 – 11/2024
Project Reference: TED2021-129540A-I00
In CONVERT, we propose to use emerging spintronic phenomena to convert the waste heat produced during computing into reusable electricity and store it in local, miniaturized solid-state batteries. This new concept can lead to significant energy saving in future data storage and processing devices, thus reduce the ever-increasing energy bill of the IT sector.
Detailed Description: Information technologies (IT) have become an essential part of our lives more than ever. The future of the IT revolution requires faster connectivity and data processing and larger data storage capability, which comes at a high cost. With the current pace, ITs energy consumption will reach ~21% of the global energy by 2030 [Nature 561, 163 (2018)]. Global energy production heavily (>80%) depends on oil, coal, and natural gas with significant greenhouse gas emissions; therefore, IT consumption will increasingly contribute to global warming in the current synopsis. CONVERT aims to make an immediate impact on this pessimistic scenario by offering environmentally-friendly energy-saving solutions to the IT sector.
Data processing continuously needs power. The large amount of electricity going through microcircuits creates waste heat, a fundamental issue in microelectronics, even more so when their size is reduced. Heat dissipation inevitably generates temperature gradients between heat sources (e.g., transistors, memory, and processing units) and sinks, which gives us an opportunity for its repurposing. In CONVERT, we propose to employ emerging spintronic phenomena to convert the waste heat produced during computing into reusable electricity and store it in local, miniaturized solid-state batteries.
Recently, tremendous progress in understanding the transport properties of materials at the nanoscale has transformed spintronic research and applications. In particular, combining materials with distinct properties has enabled the study of intricate relationships between the various degrees of freedom in solids, leading to groundbreaking discoveries. One such example is the spin Seebeck effect, where temperature gradients across a magnetic material generate pure spin currents without accompanying charge, which can be injected into an adjacent metal through the interface. Inverse spin Hall effect, another transport phenomenon of paramount importance, then converts the incoming spin current into electricity with high efficiency. This two-step process of converting heat flow to charge current
through spintronic phenomena is commonly called spintronic thermopower generation and lies at the heart of this proposal. Independently of the above, there is a growing interest in energy harvesting at microscale using thin-film solid-state batteries. They offer viable solutions to locally storing electricity in IT devices that could revolutionize the upcoming era of the Internet of Things. Solid-state batteries, thus, provide an excellent platform to harness the electricity produced through the spintronic thermopower, a concept yet to be realized.
Based on the above considerations, we will:
- Engineer materials and interfaces to maximize the heat-to-spin and spin-to-charge conversion efficiency beyond the state-of-the-art.
- Develop disruptive devices concepts to increase the spintronic thermopower output to technologically relevant magnitudes.
- Demonstrate a CMOS-compatible proof-of-concept device including a thin-film solid-state battery rechargeable by spintronic thermopower.
Overall, CONVERT will provide breakthrough knowledge and game-changing solutions for micro-energy harvesting in IT devices. The new concepts will lead to significant energy saving in future data storage and processing, thus helping alleviate precariously increasing energy needs of the IT sector.