David Broido1,Chunhua Li1,Nakib Protik2,Pablo Ordejón3,Miguel Pruneda3
Boston College1,Humboldt-Universität zu Berlin2,Catalan Institute of Nanoscience and Nanotechnology3
David Broido1,Chunhua Li1,Nakib Protik2,Pablo Ordejón3,Miguel Pruneda3
Boston College1,Humboldt-Universität zu Berlin2,Catalan Institute of Nanoscience and Nanotechnology3
In doped semiconductors and metals under an applied electric field or temperature gradient, momentum transfer between charge carriers and phonons through electron-phonon interactions boosts the thermoelectric power, a phenomenon known as electron-phonon drag [1, 2]. Using a recently-developed first principles approach to solve the coupled electron and phonon Boltzmann transport equations [3], we have examined the thermoelectric transport coefficients (electrical conductivity, Seebeck and Peltier thermopowers, and electronic and phonon thermal conductivities) in doped semiconductors. Excellent agreement is obtained with the measured thermopower of Si across a wide range of charge carrier densities and extending to the strong drag regime at low temperatures. Enormous enhancements to the thermopower, <i>S</i>, and thermoelectric power factor, <i>PF</i>, of lightly doped diamond are revealed [4]: Around 100 K, <i>S</i> and <i>PF</i> values of around 100,000 μV K<sup>-1</sup> and 7000 μW K<sup>-2</sup> cm<sup>-1</sup>, respectively, are achieved. These values are much larger than the corresponding previously reported record measured values in the correlated metal, FeSb<sub>2</sub>, and they also occur at significantly higher temperatures. The remarkable behavior stems from exceptionally weak anharmonic phonon decay at low <i>T</i> that minimizes dissipation of the phonon current, a feature that also gives large thermal conductivity thereby preventing diamond from being a useful thermoelectric material, and even when accounting for phonon frequency filtering [5].<br/><br/>[1] R. Peierls, Ann. Phys. 396, 121 (1930).<br/>[2] L. E. Gurevich, Zh. Eksp. Theor. Fiz. 16, 193 (1946).<br/>[3] N. H. Protik, C. Li, M. Pruneda, D. Broido, P. Ordejón, npj Comput. Mater. 8, 28(2022).<br/>[4] C. Li, N.H. Protik, P. Ordejón, D. Broido, Mat. Tod. Phys. 27, 100740 (2022).<br/>[5] J. Zhou, B. Liao, B. Qiu, S. Huberman, K. Esfarjani, M. S. Dresselhaus, G. Chen, Proc. Natl. Acad. Sci. 112 14777 (2015).