Ultrahigh Hole Mobility in Monolayer WSe₂ Enabled by Spin-Orbit Suppression of Intervalley Scattering

Monolayer WSe₂ has recently been identified as a top contender for ultrascaled p-channel transistors, exhibiting record-high room-temperature hole mobilities exceeding 1000 cm²/Vs [Phys. Rev. Lett. 132, 056303 (2024); Nat. Nanotechno. 19, 948 (2024); npj Comput. Mater. 10, 229 (2024)]. Here using advanced ab initio Boltzmann transport simulations, we reveal the microscopic mechanisms driving this remarkable transport properties. By including GW quasiparticle corrections for electronic band structure and long-range dipole and quadrupole effects for electron-phonon interactions, we achieved highly accurate results with phonon-limited hole mobility of 931 cm²/Vs at room temperature, closely matching experimental observations. This outstanding hole mobility is attributed to the combined reduction of K-K and K-K′ intervalley scattering driven by spin-orbit-induced valley splitting and spin-valley locking, along with inherently weak polar and piezoelectric coupling. Our findings indicate that monolayer WSe₂ is a front-runner for future high-mobility p-type electronics, and spin-orbit coupling is crucial for the design of high-mobility 2D semiconductors.