اميرحسين نقدي يوسف ابادي

This study investigates the phenomenon of quantum charge pumping in a monolayer structure composed of Ti₂C MXene using the theoretical approach of the scattering matrix within the adiabatic approximation framework. MXenes, as a novel class of two-dimensional materials with unique electronic properties, provide a suitable platform for exploring quantum phenomena. Initially, the problem of quantum transport is analyzed considering a single static potential barrier, based on parameters such as the angle of incidence an‎d the energy of incoming electrons. The analysis is then extended to a structure consisting of two static potential barriers, where the effects of variables such as the distance between the barriers (L) an‎d the width of each barrier (D) on the transport characteristics of the system are carefully eva‎luated. Finally, the generation of a DC electron current in the absence of an external bias is studied by modeling two oscillating potential barriers with a phase difference (ϕ) between them. The main objective of this research is to provide a comprehensive analysis of the influence of key structural an‎d dynamical parameters — including the angle of electron incidence, the distance between barriers, barrier width, an‎d oscillation frequency (ω) — on the quantum pumped current. The results indicate that the pumped current reaches its maximum under normal incidence an‎d decreases continuously with increasing angle of incidence. It is also shown that the pumped current exhibits clear oscillatory dependence on both the barrier separation an‎d their width, such that certain values of these parameters allow for the optimization of pumping efficiency. Moreover, it is observed that increasing the oscillation frequency enhances the pumped current. By employing the three-ban‎d tight-binding model an‎d performing scattering matrix computations, this thesis enables a detailed an‎d in-depth analysis of quantum transport behavior. The findings of this research highlight the significant potential of Ti₂C MXene in the design an‎d development of the next generation of nanoelectronic devices, including high-precision single-electron pumps, accurate current sources.

پمپاژ كوانتومي بار، مكسين Ti_2 C، ترابرد الكتروني، ماتريس پراكندگي، تقريب بي‌دررو، مواد دوبعدي، مدل سه‌نوار

Quantum charge pumping, Ti2C MXene, Electron transport, Scattering matrix, Adiabatic limit, 2D Materials, Three bands model

AmirHossein Naghdi YousefAbadi

Dr. Edris Faizabadi