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2/ Back in 2018 I derived a pretty exciting (to me) new result about the thermoelectric effect, which is the ability of a material to convert waste heat into electric power.
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@MIT news has a very nicely written article about our recent work on the thermoelectric effect in semimetals: news.mit.edu/2018/materials I gave this talk at a conference recently and one old professor was very excited: "Topological materials might finally be useful for something!"
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6/ But one of these experiments was a little _too_ good. The thermopower (the ratio of temperature difference applied to voltage difference created) rose by more than two orders of magnitude in a magnetic field. Even in conditions where our theory was not obviously applicable.
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7/ The published explanation was that this measurement was a confirmation of our theory. But I wasn't sure, so I set my graduate student Xiaozhou Feng to think critically about whether perhaps the theory I had written down was the wrong explanation.
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8/ What a good decision that was! We ended up showing that there was a different mechanism at work in this material, which gave an even more dramatic field-enhancement of thermopower.
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9/ Even better, this mechanism turned out to be generic for all "compensated" systems, which are materials that carry electric current simultaneously through positive and negative charges. This opens the door to a much wider range of materials as efficient thermoelectrics.
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I was just reading about the MMRTG used on Mars Rovers and they seem to have an awful power efficiency of ~5% (the plutonium generates ~2000W of heat, but the rovers get only 110W of electricity out of it). Do you think there's potential for higher efficiency using your results?
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I think there's definitely potential. It's still pretty far from a specific proposal for a working device, and at this stage I still wouldn't bet even odds on this working out. But there's a core idea that I like, and I hope will go somewhere.
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space is a particularly attractive application since above a particular combo of size and distance, solar doesn't work and MMRTGs are pretty much the only game in town for power
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