Electronic, Optical, and Magnetic Properties of Doped Triangular MoS2 Quantum Dots: A Density Functional Theory Approach

A theoretical investigation on electronic states in triangular MoS2 quantum dots of different sizes is performed within density functional theory first-principles formalism. Herein, the associated interband optical response from real and imaginary parts of the dielectric function is calculated. The study considers both undoped and Al-, Si-, and P-doped systems. Spin-related magnetic properties are considered through the evaluation of total magnetic moment. It is revealed that small enough structures have a semiconductor character, but evolve to seemingly half-metallic with increasing dot size. Nonzero magnetic response is attributed to edge effects. Magnetic behavior of doped systems deviates from the linear dependence of the total magnetic moment with size occurring in the undoped case, producing situations with higher total momentum values. It is found that increasing the doping density may have certain influence over total magnetic moment response of the structures, although edge dominance is kept all the way. Optical properties are not as sensitive to incident light polarization, but they actually do with regard to the particular spin orientation. Calculation for the refraction index in the triangular quantum dots shows values still below the accepted in the MoS2 monolayer case, although a correct trend of variation is reported in this sense.

Automated summary

A theoretical investigation on the electronic states in triangular MoS2 quantum dots of different sizes is conducted using density functional theory. The results show that the magnetic properties of the quantum dots evolve from being semiconductor-like to nearly half-metallic with increasing size. Doping can alter the magnetic behavior of the dots, and the doping density can affect the total magnetic moment response. The optical properties are not sensitive to incident light polarization, but they do depend on the spin orientation.