臺灣博碩士論文加值系統

在本篇論文裡,我們研究圓柱殼狀導體加上磁通量管的效應.磁通量管置於
圓柱殼內,平行圓柱軸方向.因為電子被局限在圓柱殼上,沒有感到磁場,此
種是Aharonov-Bohm 效應.在薄殼近似下,我們得到有磁通量管下的電子
態.當加上一個單位的磁通量,而且磁通量管偏移大於0.7倍的圓柱殼半徑
時,我們可以得知本徵能量對於磁通量管的偏移是很靈敏的.用以上的電子
電態,我們可以研究這系統的等離子模.磁通量管偏移小 0.7倍的圓柱殼半
徑時阻尼區沒怎麼變化,大於0.7倍圓柱殼半徑時,則阻尼區變化很快.最後
我們用數值結果來說明我們的結論.

We study the response of cylindrical conducting shell to the
presence of a magnetic flux tube. The flux tube orients
parallel to the symmetry axis of the shell and locates entirely
inside the shell. Since the conduction electron are confined
within the shell, they do not experience the presence of the
magnetic field , and the effect of the flux tube on the
electronic response of the shell is a purely Aharonov-Bohm-type
effect. Within a thin-shell approximation, we have obtain the
electron states of the shell in the presence of a magnetic flux
tube. For the case of an integral flux quanta in a cylindrical
shell of a radius□, we show that the electron eigen-energies
are sensitive to the location R of the flux only for R/□ >
0.7. Using these electron states, we study the plasmon modes on
the location of the flux tube. An off-centered flux tube breaks
the rotational symmetry of the system and gives rise to a
complicated damping region which in turn gives rise to
complicated branches of plasmon modes. Besides, for the case of
an integral flux quanta , we show that the damping region
remains unchange in the region 0 < R/□≦ 0.7. Rapid variation
in the damping region occurs only after R/□ > 0.7. This
dependence of the damping region on R/□ is closely related to
the feature of the electron states, Finally, numerical examples
are given to illustrate our conclusions.