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arXiv 2304.01616cond-mat.mes-hall
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几何对称性破缺和非线性可以提高热电功率

Geometric symmetry breaking and nonlinearity can increase thermoelectric power

Jonatan Fast, Hanna Lundström, Sven Dorsch, Lars Samuelson, Adam Burke, Peter Samuelsson, Heiner Linke

AI总结:

本文提出通过几何对称性破缺与非线性传输设计提高热电转换的填充因子(FF),突破线性响应0.25的极限,从而显著提升短路电流、开路电压和最大功率,为热-电能量转换器性能优化提供了新策略。

摘要:

直接的热-电能量转换器通常在线性区间运行,其中实际最大功率相对于理想最大功率的比值,即所谓的填充因子(FF),为0.25。通过提高FF,有可能将最大功率提高至多四倍,但这仅在非线性传输区间才可能实现,且此前很少被考虑。在此,我们基于基本的对称性考虑表明,能够提高FF的主导阶非线性项需要具有空间对称性破缺的器件。为了在实验上展示这样一个系统,我们研究了在单根半导体纳米线中通过外延定义的不对称能量势垒的非线性热电传输。我们在实验和理论中发现,我们可以将FF提高到线性响应极限0.25以上,同时伴随着短路电流、开路电压和最大功率的急剧增加。我们的结果表明,几何对称性破缺结合非线性行为的设计代表了一种提高热-电能量转换器性能的设计策略,例如在热载流子光伏、热光伏或各向异性热电材料中。

英文摘要:

Direct thermal-to-electric energy converters typically operate in the linear regime, where the ratio of actual maximum power relative to the ideal maximum power, the so-called fill factor (FF), is 0.25. By increasing the FF one can potentially increase maximum power by up to four times, but this is only possible in the nonlinear regime of transport and has previously rarely been considered. Here we show, based on fundamental symmetry considerations, that the leading order non-linear terms that can increase the FF require devices with broken spatial symmetry. To experimentally demonstrate such a system, we study nonlinear, thermoelectric transport across an asymmetric energy barrier epitaxially defined in a single semiconductor nanowire. We find in both experiment and theory that we can increase the FF above the linear-response limit of 0.25, accompanied by a drastic increase in short circuit current, open-circuit voltage and maximum power. Our results show that geometric symmetry breaking combined with the design of nonlinear behaviour represent a design strategy for increasing the performance of thermal-to-electric energy converters such as in hot-carrier photovoltaics, thermophotovoltaics or in anisotropic thermoelectric materials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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