Concurrent high thermal conductivity and high carrier mobility in tetragonal tantalum nitride

Abstract

Semiconductor devices demand materials that exhibit exceptional carrier and heat transport; however, such materials have remained exceedingly scarce. Using rigorous first-principles calculations, we identify tetragonal tantalum nitride (t-TaN) as a narrow bandgap semiconductor that uniquely achieves both high thermal conductivity (κ) and high carrier mobility (μ). At room temperature, t-TaN demonstrates an extraordinary κ of up to 677 W m−1 K−1, surpassing that of most widely used semiconductors. This remarkable κ arises from the synergistic effects of phonon bunching and a substantial frequency gap in the phonon spectrum, which significantly suppresses phonon–phonon scattering. Even more strikingly, t-TaN exhibits exceptional hole μ exceeding 4700 cm2 V−1 s−1 at room temperature, outperforming all known high-κ bulk semiconductors. This ultrahigh μ is attributed to its elevated Fermi velocity and weak electron–phonon coupling, stemming from its unique electronic and phononic structures. These findings position t-TaN as a compelling candidate for advanced electronic and optoelectronic applications, while also offering a transformative perspective for discovering high-performance semiconductors with dual advantages.