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arXiv · 2608.07097

Net and Hidden Spin-Valley Locking Enable Ultrahigh Hole Mobility in Covalent Bulk WN$_2$

Rong-Tian Pang·Zhongjuan Han·Jiayi Gong·Jiangang He·Jin-Jian Zhou·Yugui Yao
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Abstract

High carrier mobility at room temperature underpins high-performance electronics, yet high hole mobility remains rare in bulk semiconductors. Spin-valley locking can suppress intervalley scattering and enhance mobility, but it is limited to materials with broken inversion symmetry. Hidden spin polarization offers a possible route beyond this constraint, although whether its compensated spin textures could protect charge transport remains unclear. Using ab initio electron-phonon and transport calculations, we show that the two hexagonal phases of bulk WN$_2$ realize net and hidden spin-valley locking and exhibit ultrahigh room-temperature hole mobilities. In non-centrosymmetric $α$-WN$_2$, a large valley spin splitting produces net spin-valley locking that nearly eliminates phonon-mediated intervalley scattering. In centrosymmetric $β$-WN$_2$, hidden Zeeman-type spin polarization yields a compensated, sector-resolved spin texture that reverses between valleys and suppresses intervalley scattering as effectively as the net locking does. The stiff W-N/N-N covalent network further keeps the remaining intravalley scattering weak. Our results establish hidden spin polarization as an effective transport-protection mechanism and extend spin-valley engineering to centrosymmetric bulk semiconductors.

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Rong-Tian Pang, Zhongjuan Han, Jiayi Gong, Jiangang He, Jin-Jian Zhou, Yugui Yao. 2026-08-07. Net and Hidden Spin-Valley Locking Enable Ultrahigh Hole Mobility in Covalent Bulk WN$_2$. https://arxiv.org/abs/2608.07097

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