Gallium oxide is a promising material for power conversion electronics, yet its widespread application is limited by low carrier mobility. In this work, we investigate the effect of strain on the electron and hole mobilities of $\beta \text{−}{\mathrm{Ga}}_2{\mathrm{O}}_3$. Using first-principles calculations, we find that the electron mobility is two orders of magnitude larger than the hole mobility. Furthermore, we show that tensile strain enhances the electron mobility while reducing the hole mobility. To understand this behavior, we analyze the electronic band structure. The lowest conduction bands of $\beta \text{−}{\mathrm{Ga}}_2{\mathrm{O}}_3$ are mainly composed of Ga and O $s$ orbitals. Under tensile strain, the electron effective mass and scattering rate decrease, whereas the group velocity increases. In contrast, the valence bands originate primarily from O $p$ states, leading to an increase in the hole effective mass and scattering rate, accompanied by a reduction of the group velocity with strain. We also investigate the long-range interaction between longitudinal optical phonons and charge carriers. At the Brillouin-zone center, polar longitudinal optical phonons dominate electron scattering, while both acoustic and optical phonons contribute significantly to hole scattering. Overall, this study provides a detailed understanding of strain-engineered electron and hole transport in $\beta \text{−}{\mathrm{Ga}}_2{\mathrm{O}}_3$, offering insights for the design of high-performance semiconductor devices.

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• Charge dynamics
• Electrical conductivity
• Electrical properties
• Ionic conductivity
• Boltzmann theory