With the development of molecular beam epitaxy (MBE) technology and metal organic chemical vapor deposition (MOCVD) technology

there has been great interest in investigating quantum dot both in material science and condensed state physics field. Due to size of quantum dot was small

they had a series of new and serious character

for example

quantum size effect

quantum coherent effect

quantum tunnel effect

coulomb resistance effect and surface effect

etc

.

these had brought infinite chance and hope on development and use of new materials. Especially

electron in quantum dot was subject to a strong three-dimension (3D) confinement

so that quantum effect was quite different from those of the bulk materials

these would brought about great society benefit and economic benefit. So many scientists has been investigating properties of quantum dots. Zhu J L

et al

. studied the properties of spherical quantum dot by using a few bodies method

results indicated that binding energy of donor state had depended on shape

dimension and confined potential of the quantum dots. Charrour R

et al

. studied the ground state binding energy of hydrogenic impurity in cylindrical quantum dot that subjected to external strong magnetic field by using the variational procedure and considering an infinite confined potential on all surface of the system. They found that the impurity binding energy depended strongly on the impurity position

magnetic field strength and the dot size(radius and height). Zhou H Y and Gu Shiwei had studied the properties of strong-coupling magnetopolaron in a disk-shape quantum dot

they pointed that the ground state energy and the excited state energy depended on resonance frequency and confined strength. The properties of magnetopolaron with electron-LO-phonon weak-coupling in cylindrical quantum dot

which was in parabolic potential

were investigated by using the linear combination operator and unitary transformation methods. Numerical calculations for ZnS quantum dot indicated that the ground state energy increased with increa sing characteristic frequency and cyclotron-resonance frequency

since vibration energy increased with increasing characteristic frequency and additional energy in external magnetic field increased with increasing cyclotron-resonance frequency

the energy of magnetiopolaron changed position from negative when characteristic frequency(or cyclotron-resonance frequency) increased to the value

for example

which was 0.27ω

LO

for the case of cylinder height L =20 nm and cyclotron resonance frequency ω

c

=0.5ω

LO

(or ω

c

was 0.5ω

LO

for the case of L=20 nm and characteristic frequency ω

0

=0.27ω

LO

). The ground state energy increased with increasing cylinder height

the smaller cylinder height was

the faster it increased

the energy of magnetopolaron also changed positive from negative when cylinder height decreased to 33.1 nm for the case of ω

c

=ω

0

=0.5ω

LO

. In short

ground state energy of bounding magnetopolaron in cylindrical quantum dot had something to do with size of quantum dot

external magnetic field and characteristic frequency.