标题: 複層量子結構中雜質能階及外加磁場效應之研究
Studies on the Impurity Energy Levels of Multi-layer Quantum Structures and the Effect of External magnetic Field
作者: 林銘杰
Lin, Ming-Chien
褚德三
Der-San Chuu
電子物理系所
关键字: 複層量子點;複層量子線;Coated quantum dot;Coated quantum wire
公开日期: 1997
摘要: The energy states of a hydrogenic impurity located at the
center of a quasi-zero dimensional coated quantum dot (CQD) are
investigated. We also study the electronic energy levels in a
quasi-one dimensional coated quantum wire (CQW) with an applied
magnetic field along the wireaxis. In both of the CQD and CQW
systems, we solve the Schroedingerequations analytically, and
obtain the electronic eigenstates as functionsof the radius of
the CQD and CQW and the material parameters. Our resultsshow
that the ground state energies for both systems are deeply
influencedby the shell thickness and approach the correct limit
of the bulk case, asthe radius of the inner layer becomes very
large. It is also found that theground state energy of the CQD
is higher than that of the CQW because the former system has one
more dimensional confinement. However, the ground state energies
for both two systems approach the same value, as the
shellpotentials are negative enough. In the study of the effect
of external magneticfield, our results show that in a moderate
magnetic field strength availablein the laboratory, the magnetic
length is usually large. Thus the potentialbarrier is always the
winner of the competition with a magnetic field in the coated
quantum wire without impurity. Image potential effect in the
Schroedinger equation is ignored and the effective mass
approximation is employed. The eigenfunctions can be expressedin
terms of the Whittaker functions. For numerical calculations, we
onlycalculate the ground state energy, although the excited
state energies can beobtained straightforwardly. We must
emphasis here the numerical method employedin this thesis is
novel and has general significance.
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT860429008
http://hdl.handle.net/11536/63016
显示于类别:Thesis