Anomalous lattice thermal conductivity driven by all-scale electron-phonon scattering in bulk semiconductors

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Electron-phonon coupling (EPC) has been broadly considered to govern the charge transport in solids, whereas its effect on thermal conductivity, especially for semiconductors at ambient temperatures, is a widely debated issue in condensed-matter physics. Employing state-of-the-art first-principles calculations to quantify all the possible scattering factors, we show the dominant role of EPC in phonon transport of $n$-doped GaSb, which yields an unprecedented reduction of lattice thermal conductivity and triggers anomalous temperature-independent behavior. The significant EPC impact hinges on the joint effect of multiple conduction pockets, large EPC strength, and bunched heat-carrying acoustic branches, provoking strong electron-phonon scattering to surpass the intrinsic phonon-phonon scattering for all-scale phonons, in contrast to the case in silicon that only long-wave phonons can be scattered by carriers even at high doping level. This work advances the understating of phonon transport in doped semiconductors and stimulates potential heat management application of anomalous thermal conductivity.