Quantum Tunneling Simulator — Electron Scattering from a Rectangular Barrier Interactive

Interactive 3D quantum tunneling laboratory: scatter an electron from a rectangular potential barrier, vary energy, barrier height and width, and sample transmitted versus reflected outcomes against the exact transmission coefficient.

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About the Quantum Tunneling Simulator

Inspect an electron scattering from a rectangular potential barrier. The real wave oscillates while its stationary probability density and transmitted flux follow the boundary-matched solution.

What the simulator shows

• An incident and reflected region, a rectangular potential barrier, the barrier-region wave, a transmitted region and reflection / transmission counters. • Controls for incident electron energy (eV), barrier height (eV), barrier width (nm) and scattering trials per second. • Four tabs: Quantum bench, Probabilities & measurements, Experiments (with built-in model checks), and Learn & assess.

The mathematics

ℏ²/(2me) = 0.03809982 eV·nm² and k = √(E/0.03809982). For E < V, κ = √[(V−E)/0.03809982] and T = {1 + V² sinh²(κa)/[4E(V−E)]}^−1, with R = 1 − T. For E > V, sinh is replaced by sin and V−E by E−V. The wave and its derivative match at both interfaces.

Model boundaries

This is a one-dimensional stationary nonrelativistic electron scattering model with a real rectangular potential and equal exterior potentials. It makes no wavepacket travel-time or tunneling-time prediction and has no many-body or semiconductor band calculation. The carrier phase animation is slowed arbitrarily.

Frequently asked questions

Does E below the barrier require zero transmission?

No. A finite barrier permits a nonzero transmitted probability flux.

Is the moving carrier a prediction of tunneling time?

No. This is a stationary scattering solution with slowed phase animation.

What happens to transmission as the barrier gets thicker?

Transmission becomes exponentially small (the "Thick barrier" preset), but the wave is not truncated at the boundary; a thin barrier gives much higher transmission.

Can reflection occur when the electron energy is above the barrier?

Yes. Reflection can still occur above the barrier, and changing the width produces interference resonances (the "Above barrier" preset).

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