Controllable ferroelectricity and bulk photovoltaic effect in elemental group-V monolayers through strain engineering

Abstract

In this paper, based on the first-principles calculation combined with a $k\ifmmode\cdot\else\textperiodcentered\fi{}p$ model, we systematically study the ferroelectricity and bulk photovoltaic effect (BPVE) in elemental group-V monolayers. Our results indicate that the electric polarization in group-V monolayers can be effectively tuned by external uniaxial strain, showing a perfect linear relationship. In addition, the Berry curvature and BPVE are well correlated to spontaneous polarizations, which are dominated by structural distortion. Remarkably, a quadratic relation between the shift current and the spontaneous polarization is observed in group-V monolayers. Accordingly, by manipulating the structural distortion through strain engineering, the BPVE can be generated in a controllable manner. Our work not only establishes the polarization-dependent BPVE in ferroelectric materials, but also paves the way for the development of BPVE-based ferroelectric devices.