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nnp:cbr_1d_potential [2020/03/12 11:21] takuma.sato [Single Potential Barrier] |
nnp:cbr_1d_potential [2024/01/03 16:50] stefan.birner removed |
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<figure step_gamma> | <figure step_gamma> | ||
- | {{:nnp::transmission_1dstep_gamma.png?direct&600}} | + | {{:nnp::transmission_1dstep_gamma.png}} |
</figure> | </figure> | ||
<figure step> | <figure step> | ||
- | {{:nnp::transmission_1dstep.png?direct&600}} | + | {{:nnp::transmission_1dstep.png}} |
+ | <caption>Transmission spectrum for a step potential. Transmission is only allowed above the step.</caption> | ||
</figure> | </figure> | ||
==== Quantum Well ==== | ==== Quantum Well ==== | ||
- | Similarly a quantum well structure can be simulated. | + | Similarly a quantum well structure can be simulated. The well width is w=10nm here. |
<figure well gamma> | <figure well gamma> | ||
- | {{:nnp::transmission_1dwell_gamma.png?direct&600}} | + | {{:nnp::transmission_1dwell_gamma.png}} |
</figure> | </figure> | ||
- | Again the transmission of electron with energy lower than $E_{\mathrm{barrier}}$ is impossible because the barrier is infinitely thick. Above $E_{\mathrm{barrier}}$ the spectrum shows an oscillatory behaviour. | + | Again the transmission of electron within the barriers is impossible because the barrier is infinitely thick. Above 0eV, the spectrum shows an oscillatory behaviour. |
<figure well> | <figure well> | ||
- | {{:nnp::transmission_1dwell.png?direct&600}} | + | {{:nnp::transmission_1dwell.png}} |
+ | <caption>Transmission spectrum for the quantum well structure. The dashed line marks the top of the barrier.</caption> | ||
</figure> | </figure> | ||
==== Double Potential Barrier ==== | ==== Double Potential Barrier ==== | ||
- | Finally we consider a double barrier structure with wall width 10 nm. The distance between the barriers is 10 nm. | + | Finally we consider a double barrier structure with wall width 10 nm. The barrier interval is 10 nm. |
<figure double barrier gamma> | <figure double barrier gamma> | ||
- | {{:nnp::transmission_1ddoublebarrier_gamma.png?direct&600}} | + | {{:nnp::transmission_1ddoublebarrier_gamma.png}} |
</figure> | </figure> | ||
Line 72: | Line 74: | ||
<figure resonant> | <figure resonant> | ||
- | {{:nnp::transmission_1ddoublebarrier_resonant.png?direct&600}} | + | {{:nnp::transmission_1ddoublebarrier_resonant.png}} |
<caption>Probability distribution $|\psi(x)|^2$ of the two resonant modes.</caption> | <caption>Probability distribution $|\psi(x)|^2$ of the two resonant modes.</caption> | ||
</figure> | </figure> | ||
- | In the transmission spectrum, one can clearly see the 100% transmission at the energies of the resonant states in the quantum well. Please note that the vertical axis is logarithmic scale. | + | In the transmission spectrum, one can clearly see the sharp transmission at the energies of the resonant states in the quantum well. Please note that the vertical axis is logarithmic scale. |
<figure double_barrier> | <figure double_barrier> | ||
- | {{:nnp::transmission_1ddoublebarrier.png?direct&600}} | + | {{:nnp::transmission_1ddoublebarrier.png}} |
<caption>Transmission coefficient of the double barrier structure. The spectrum has two sharp peaks below the barrier height 3.084 eV, which corresponds to the resonant mode within the barriers.</caption> | <caption>Transmission coefficient of the double barrier structure. The spectrum has two sharp peaks below the barrier height 3.084 eV, which corresponds to the resonant mode within the barriers.</caption> | ||
</figure> | </figure> |