Espectroscopia de tunelamento em sistemas nanoscopicos de transporte balistico
AUTOR(ES)
Gustavo Michel Mendoza La Torre
DATA DE PUBLICAÇÃO
2003
RESUMO
In this work we discuss the ballistic transport properties of non-interacting electrons in confined nanoscopic system, where the sample boundaries and a controllable impurity repulsive, such as the one induced by scanning a Atomic Force Microscope tip or using split gates technique are the only source of electron sacttering. Two quantum scenary are studied: first resonant tuneling diode of GaAs/AlGaAs (RTD) where of transport is perpendicular with the interface and mesoscopic device of confined 2DEG where of transport is parallel with the interface of the heterostructures. This systems are modelated in the aproximation of effective mass or envelope function using continuous discreet and lattice Green s function (recursive and self-energy) methods, for calculate the transmission amplitudes through system. In the case of RTD, we study the current vs voltage using the Esaki-Tsu model in function of the parameters of the heterostructures. We discuss the thermionic emission across GaAs/AlAs super lattice type double-barrier quantum well structures without X- G coupled and compared with the experiment. Also, we analized the mapping of the wave functions of discreet states in RTD: double-barrier quantum well. For the systems of confined 2DEG, we study diferent confinement potentials: quantum wire (QW), quantum point contact (QPC), open quantum dot (OQD) and any systems coupled, calculate the conductance using the Landauer-B. uttiker model. We discuss the minimal conditions for wave functions mapping in OQD using the AFM tip. Also, study the tuning of Fano resonances and continuous states using the AFM tip. Finally, we propose a quantum device of multiples functions based in a wave-function engineering in quantum dots, using two ingredients basic: firts a adequate wave function mapping and second a systematic tunning of the resonant and continuous states.
ASSUNTO(S)
espectroscopia de tunelamento fenomenos mesoscopicos (fisica) pontos quanticos poços quanticos função de onda
