TY - JOUR
T1 - Iron-based binary ferromagnets for transverse thermoelectric conversion
AU - Sakai, Akito
AU - Minami, Susumu
AU - Koretsune, Takashi
AU - Chen, Taishi
AU - Higo, Tomoya
AU - Wang, Yangming
AU - Nomoto, Takuya
AU - Hirayama, Motoaki
AU - Miwa, Shinji
AU - Nishio-Hamane, Daisuke
AU - Ishii, Fumiyuki
AU - Arita, Ryotaro
AU - Nakatsuji, Satoru
N1 - Funding Information:
Acknowledgements We thank T. Tsujikawa for assistance with thin-film fabrication. This work is partially supported by CREST (JPMJCR18T3), New Energy and Industrial Technology Development Organization (NEDO), PRESTO (JPMJPR15N5), Japan Science and Technology Agency, by Grants-in-Aids for Scientific Research on Innovative Areas (JP15H05882 and JP15H05883) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan, and by Grants-in-Aid for Scientific Research (JP16H02209, JP16H06345, JP19H00650) from the Japanese Society for the Promotion of Science (JSPS). The work at IQM was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under grant DE-FG02-08ER46544. The work for first-principles calculations was supported in part by JSPS Grant-in-Aid for Scientific Research on Innovative Areas (JP18H04481 and JP19H05825) and by MEXT as a social and scientific priority issue (Creation of new functional devices and high-performance materials to support next-generation industries) to be tackled by using post-K computer (hp180206 and hp190169). The use of the facilities of the Materials Design and Characterization Laboratory at the Institute for Solid State Physics, The University of Tokyo, is acknowledged.
Publisher Copyright:
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2020/5/7
Y1 - 2020/5/7
N2 - Thermoelectric generation using the anomalous Nernst effect (ANE) has great potential for application in energy harvesting technology because the transverse geometry of the Nernst effect should enable efficient, large-area and flexible coverage of a heat source. For such applications to be viable, substantial improvements will be necessary not only for their performance but also for the associated material costs, safety and stability. In terms of the electronic structure, the anomalous Nernst effect (ANE) originates from the Berry curvature of the conduction electrons near the Fermi energy1,2. To design a large Berry curvature, several approaches have been considered using nodal points and lines in momentum space3–10. Here we perform a high-throughput computational search and find that 25 percent doping of aluminium and gallium in alpha iron, a naturally abundant and low-cost element, dramatically enhances the ANE by a factor of more than ten, reaching about 4 and 6 microvolts per kelvin at room temperature, respectively, close to the highest value reported so far. The comparison between experiment and theory indicates that the Fermi energy tuning to the nodal web—a flat band structure made of interconnected nodal lines—is the key for the strong enhancement in the transverse thermoelectric coefficient, reaching a value of about 5 amperes per kelvin per metre with a logarithmic temperature dependence. We have also succeeded in fabricating thin films that exhibit a large ANE at zero field, which could be suitable for designing low-cost, flexible microelectronic thermoelectric generators11–13.
AB - Thermoelectric generation using the anomalous Nernst effect (ANE) has great potential for application in energy harvesting technology because the transverse geometry of the Nernst effect should enable efficient, large-area and flexible coverage of a heat source. For such applications to be viable, substantial improvements will be necessary not only for their performance but also for the associated material costs, safety and stability. In terms of the electronic structure, the anomalous Nernst effect (ANE) originates from the Berry curvature of the conduction electrons near the Fermi energy1,2. To design a large Berry curvature, several approaches have been considered using nodal points and lines in momentum space3–10. Here we perform a high-throughput computational search and find that 25 percent doping of aluminium and gallium in alpha iron, a naturally abundant and low-cost element, dramatically enhances the ANE by a factor of more than ten, reaching about 4 and 6 microvolts per kelvin at room temperature, respectively, close to the highest value reported so far. The comparison between experiment and theory indicates that the Fermi energy tuning to the nodal web—a flat band structure made of interconnected nodal lines—is the key for the strong enhancement in the transverse thermoelectric coefficient, reaching a value of about 5 amperes per kelvin per metre with a logarithmic temperature dependence. We have also succeeded in fabricating thin films that exhibit a large ANE at zero field, which could be suitable for designing low-cost, flexible microelectronic thermoelectric generators11–13.
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U2 - 10.1038/s41586-020-2230-z
DO - 10.1038/s41586-020-2230-z
M3 - Article
C2 - 32376952
AN - SCOPUS:85084222140
VL - 581
SP - 53
EP - 57
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7806
ER -