Valley Splitting in a Silicon Quantum-Dot Qubit

Silicon spin qubits confine a single electron in a gate-defined quantum dot right at a Si/SiO₂ or Si/SiGe interface — and that interface does more than trap the charge: it lifts silicon's six-fold conduction-band valley degeneracy into a two-level "valley" system with its own splitting energy, ΔE_v. This simulation renders the atomic interface with a controllable monolayer step and an electron wavefunction confined above it by a tunable vertical electric field, then computes ΔE_v from the interference between the two valley states as their relative phase winds with the step height — the same atomic-scale sensitivity that makes valley splitting notoriously uneven from qubit to qubit on a real chip. A temperature slider turns that splitting into a live thermal-leakage readout, showing exactly why a small ΔE_v threatens spin-qubit fidelity.