The anisotropic ultrahigh hole mobility in strain-engineering two-dimensional penta-SiC$_2$

Using the first-principles calculations based on density functional theory, we systematically investigate the strain-engineering (tensile and compressive strain) electronic, mechanical and transport properties of monolayer penta-SiC$_2$. By applying an in-plane tensile or compressive strain, it is easy to modulate the electronic band structure of monolayer penta-SiC$_2$, which subsequently changes the effective mass of carriers. Furthermore, the obtained electronic properties are predicted to change from indirectly semiconducting to metallic. More interestingly, at room temperature, uniaxial strain can enhance the hole mobility of penta-SiC$_2$ along a particular direction by almost three order in magnitude, $i.e.$ from 2.59 $\times10^3 cm^2/V s$ to 1.14 $\times10^6 cm^2/V s$ (larger than the carrier mobility of graphene, 3.5 $\times10^5 cm^2/V s$), with little influence on the electron mobility. The high carrier mobility of monolayer penta-SiC$_2$ may lead to many potential applications in high-performance electronic and optoelectronic devices