  A simple band model such as the effective mass approximation (EMA) can be
used to quickly obtain the lower-energy region for the band structure of
monolayer molybdenum disulfide. But the EMA band model cannot give the correct
description for the band structure in the higher-energy region. To address this
major issue, we propose an analytical band calculation (ABC) model to study
monolayer molybdenum disulfide. Important parameters of the ABC model are
obtained by fitting the three-direction band structure of monolayer molybdenum
disulfide obtained from the first-principles (FP) method. The proposed ABC
model fits well with the FP band structure calculation result for monolayer
molybdenum disulfide. We also use the ABC model to calculate physical
quantities used in carrier transport such as density of states and group
velocity. Our ABC model can be extended and further utilized for calculating
the key physical quantities of ballistic transport of 2D semiconductor
materials.
