Huynh V. Phuc

NONLINEAR ABSORPTION LINE-WIDTHS IN RECTANGULAR QUANTUM WIRES

Applying the theory of nonlinear optical conductivity for an electron—phonon system, we propose a new method to obtain the line-widths of nonlinear optical conductivity in rectangular quantum wires (RQW). General analytical expressions of the nonlinear absorption power (NLAP) are obtained in the presence of an intense external field. A two-photon absorption process is taken into the result. The dependence of NLAP on the photon energy and the wires size are numerically calculated and graphically plotted for a specific RQW. From graphs of the NLAP, we obtain line-widths as profiles of curves. The dependence of the line-widths on the temperature and parameters of a RQW are reasonable in comparison with some available theoretical and experimental results.

Linear and nonlinear magneto-optical properties of monolayer phosphorene

We theoretically study the magneto-optical properties of monolayer phosphorene under a perpendicular magnetic field. We evaluate linear, third-order nonlinear, and total absorption coefficients and relative refractive index changes as functions of the photon energy and the magnetic field, and show that they are strongly influenced by the magnetic field. The magneto-optical absorption coefficients and relative refractive index changes appear in two different regimes: the microwave to THz and the visible frequency. The amplitude of intra-band transition peaks is larger than that of the inter-band transitions. The resonant peaks are blue-shifted with the magnetic field. Our results demonstrate the potential of monolayer phosphorene as a new two-dimensional material for applications in nano-electronic and optical devices as a promising alternative to graphene.

First-principles study of the structural and electronic properties of graphene/MoS2 interfaces

In this paper, we study the structural and electronic properties of graphene adsorbed on MoS2 monolayer (G/MoS2) with different stacking configurations using dispersion-corrected density functional theory. Our calculations show that the interaction between graphene and MoS2 monolayer is a weak van der Waals interaction in all four stacking configurations with the binding energy per carbon atom of −30 meV. In the presence of MoS2 monolayer, the linear bands on the Dirac cone of graphene at the interfaces are slightly split. A band gap about 3 meV opens in G/MoS2 interfaces due to the breaking of sublattice symmetry by the intrinsic interface dipole, and it could be effectively modulated by the stacking configurations. Furthermore, we found that an n-type Schottky contact is formed at the G/MoS2 interface in all four stacking configurations with a small Schottky barrier about 0.49 eV. The appearance of the non-zero band gap in graphene has opened up new possibilities for its application in electronic device...

Linear and nonlinear magneto-optical properties of monolayer MoS2

In this work, using the compact density matrix approach, we study the linear and nonlinear magneto-optical properties of monolayer molybdenum disulfide (MoS2) via an investigation of the absorption coefficients (MOACs) and refractive index changes (RICs). The results are presented as functions of photon energy and external magnetic field. Our results show that the MOACs and the RICs appear as a series of peaks in the inter-band transitions between Landau levels, while the intra-band transitions result in only one peak. Because of the strong spin-orbit coupling, the peaks caused by the spin-up and -down states are different. With the increase in the magnetic field, both MOACs and RICs give a blue-shift and reduce in their amplitudes. These results suggest a potential application of monolayer MoS2 in the optoelectronic technology, magneto-optical, valleytronic, and spintronic devices.In this work, using the compact density matrix approach, we study the linear and nonlinear magneto-optical properties of monolayer molybdenum disulfide (MoS2) via an investigation of the absorption coefficients (MOACs) and refractive index changes (RICs). The results are presented as functions of photon energy and external magnetic field. Our results show that the MOACs and the RICs appear as a series of peaks in the inter-band transitions between Landau levels, while the intra-band transitions result in only one peak. Because of the strong spin-orbit coupling, the peaks caused by the spin-up and -down states are different. With the increase in the magnetic field, both MOACs and RICs give a blue-shift and reduce in their amplitudes. These results suggest a potential application of monolayer MoS2 in the optoelectronic technology, magneto-optical, valleytronic, and spintronic devices.

Tuning the Electronic Properties, Effective Mass and Carrier Mobility of MoS2 Monolayer by Strain Engineering: First-Principle Calculations

In this paper, we studied the electronic properties, effective masses, and carrier mobility of monolayer

Fundamental exciton transitions in SiO2/Si/SiO2 cylindrical core/shell quantum dot

\hbox {MoS}_2

Electronic properties of GaSe/MoS2 and GaS/MoSe2 heterojunctions from first principles calculations

MoS2 using density functional theory calculations. The carrier mobility was considered by means of ab initio calculations using the Boltzmann transport equation coupled with deformation potential theory. The effects of mechanical biaxial strain on the electronic properties, effective mass, and carrier mobility of monolayer