AI 中文总结
本研究通过分层筛选框架，发现MoN₂和WN₂为室温下超高本征空穴迁移率的极性半导体，揭示其性能机制并提出高迁移率材料设计新策略。
AI 中文摘要
高迁移率p型半导体是先进电子器件的核心材料，但目前仍十分稀缺。本研究采用结合第一性原理计算与玻尔兹曼输运理论的分层筛选框架，识别出$M$N$_2$（$M$=钼和钨）家族为具有超高本征空穴迁移率的极性半导体，其中1H-WN$_2$的室温空穴迁移率超过$10^{4}$~$\text{cm}^2\textrm{V}^{-1}\textrm{s}^{-1}$。该优异输运性能源于极性光学声子与声学声子散射的协同抑制，以及自旋-谷锁定诱导的谷间散射相空间减小；这些效应由反常小的玻恩有效电荷、强共价N-N键，以及基于N$_2$二聚体结构中N-$2p_x$/$2p_y$与W-$5d_{xy}$/$5d_{x^2-y^2}$的轨道杂化共同产生。本研究确立了MoN$_2$和WN$_2$作为极具潜力的高迁移率极性半导体，提出了基于晶体结构同时抑制多种电子-声子散射通道的策略，修正了高迁移率材料的设计原则。
英文摘要
High-mobility $p$-type semiconductors are essential for advanced electronic devices but remain scarce. Here, using a hierarchical screening framework that combines first-principles calculations with Boltzmann transport theory, we identify $M$N$_2$ ($M$= Mo and W) family as polar semiconductors with exceptionally high intrinsic hole mobilities. In particular, 1H-WN$_2$ exhibits a room-temperature hole mobility exceeding $10^{4}$~$\mathrm{cm^2\,V^{-1}\,s^{-1}}$. This exceptional transport performance arises from the synergistic suppression of polar-optical-phonon and acoustic-phonon scattering, together with a reduced intervalley-scattering phase space induced by spin--valley locking. These effects arise from anomalously small Born effective charges, strong covalent N--N bonds, and orbital hybridization between N-$2p_x$/$2p_y$ and W-$5d_{xy}$/$5d_{x^2-y^2}$ in the N$_2$-dimer-based structure. Our results establish MoN$_2$ and WN$_2$ as a promising class of high-mobility polar semiconductors and introduce a crystal-structure-based strategy for concurrently suppressing multiple electron--phonon scattering channels, thereby revising design principles for high-mobility materials.
Comments7 pages, 4 figures
