Using high-accuracy many-body quantum Monte Carlo (QMC) methods, we study the effect of interlayer coupling on the properties of two-dimensional freestanding bilayers (BLs) of ${\mathrm{MoS}}_2$ and phosphorene. The properties of the two BL-materials are very different and largely determined by the interlayer interaction, which is purely van der Waals in ${\mathrm{MoS}}_2$ and partially electronic/chemical in phosphorene, resulting in a modest layer-dependent property modulation in ${\mathrm{MoS}}_2$ and strong modulation in phosphorene. Multireference and symmetry considerations are used to construct state-of-the-art accuracy QMC trial wave functions. We determine the quasiparticle band gaps for both materials, ${\mathrm{\Delta }}_{\mathrm{\Gamma }\to \mathrm{K}}^{\text{qp}}=2.45\pm 0.05\mathrm{eV}$ in BL-${\mathrm{MoS}}_2$ and ${\mathrm{\Delta }}_{\mathrm{\Gamma }\to \mathrm{\Gamma }}^{\text{qp}}$=1.59 $\pm 0.1\mathrm{eV}$ in BL-phosphorene. These benchmark band-gap values make it possible to consolidate the interpretation of the widely scattered experimental and theory data.

Close

PrevNext

View figure in article

• Electronic structure
• 2-dimensional systems
• Phosphorene
• Transition metal dichalcogenides
• Diffusion quantum Monte Carlo
• First-principles calculations