Electric field tuning of the properties of monolayer hexagonal boron phosphide

Abstract

External factors are known to significantly modify the properties of low-dimensional materials. Here, we show that a perpendicular electric field can tune the fundamental electrical, thermal, and magnetical features of monolayer boron phosphide (MBP). We use the traditional Boltzmann approach, two-band tight-binding Hamiltonian model, and the Green’s function technique and particularly focus on the bandgap, electronic density of states, electronic heat capacity (EHC), and paramagnetic susceptibility (PMS) of MBP. We clarify the unique role of bias polarity on these quantities. The system undergoes a pseudo-Lifshitz phase transition when the electric field is equal to the pristine bandgap of MBP and accordingly, the massive Dirac fermions become massless. Additionally, the electron–hole symmetry breaking stemming from the variation of the Van Hove singularities with the electric field is discussed. We further show that the modulated electronic phase of the system leads to the tuning of EHC and PMS depending on the electric field direction. We believe that the present results are useful for various logic applications based on MBP.