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By using the nonequilibrium Green function method, the photon-assisted electron transport through a graphene-based device similar to STM model is studied theoretically and numerically. The device is composed of a single central site (quantum dot) modulated by an oscillating electric field, a one-dimensional quantum wire and a two-dimensional graphene sheet. Some interesting results on transmission probability and current–voltage ($I$–$V$) characteristics of the device are given in this paper. In the presence of an oscillating electric field, we find that besides the central two transmission peaks caused by graphene part, there appear photon-assisted peaks which are distributed on both sides of the Fermi level. The positions of the photon-assisted peaks are linear to the frequency of the oscillating electric field, and the widths of the photon-assisted peaks are relevant to the amplitude of the oscillating electric field. It is found that the current–voltage graphs exhibit step growth due to the existence of photon-assisted tunneling. We hope these results may have guidance meaning for the fabrication of optoelectronic devices.

This research delves into the fascinating transmission characteristics of a system with variable mass, confined by a Coulomb-like potential. By utilizing an analytic approach to transmission probability, we were able to unveil the intriguing features that are observed experimentally in a specially designed two-dimensional lattice. This lattice was engineered to manipulate itinerant electrons through entanglement, resulting in variable masses as they traverse the lattice. To build our model system, we utilized the displacement operator approach to the position-dependent effective mass theory. This allowed us to investigate the effects of different configurations of leads, system geometries and lattice deformations on the transmission characteristics of the system. The resulting data showed that the model system was highly sensitive to these parameters, which led to various interesting features. First, we observed Andreev-like reflections, which occur when a particle is reflected as a hole, resulting in the transfer of both energy and charge. Another feature was reflectionless transmission, in which the transmission probability of a particle is close to unity, and almost no reflection occurs. We also observed complete localization of charge carriers, where the transmission probability is effectively zero, indicating that the charge carriers are completely confined within the lattice. Our findings demonstrate the remarkable versatility of the effective mass approach in the modeling of physical systems. By unraveling the intricate relationships between system parameters and transmission probability, we have gained new insights into the behavior of itinerant charge carriers in lattice structures. These insights may guide the design and development of novel electronic devices with enhanced performance and functionality.

We theoretically investigate the transmission probability and the persistent current in an open quantum ring threaded by the magnetic flux. From the numerical results, we find that the two observable quantities both show a periodic characteristic with the increase of the magnetic flux, and they strongly depend on the dimensionless wave vector and the central angle as well as the magnetic flux.

Employing the non-equilibrium Green’s function technique, we have obtained the formula for dc current of two one-dimensional multi-quantum dot arrays, which couple to each other via tunneling coupling between two quantum dots connected to four leads, respectively. The retarded Green’s function is a staircase type, terminating at the four leads. Furthermore, the four quantum dots case is demonstrated. The influence of inter-dot coupling strength and quantum dot energy level on the transmission probability for TL, TM and TN branches is investigated. A non-resonant band is observed. By adjusting energy levels of quantum dots, a resonance emerges in the region of the non-resonance band. The system can be used as a quantum switch.

A correct formula for fusion cross-section is proposed for better understanding of light nuclear fusion plasma. It is based on the one-dimensional method. The fusion cross-section and the Maxwellian rate parameters of the ³He+⁶Li system are calculated. The obtained results are in good accord with theoretical data of other researchers.