Ab Initio Prediction of Noncollinear Magnetic States of the Quantum Phosphorus Qubit in a Silicon Lattice.

The problem of the practical implementation of quantum computers is an important scientific and technological task at the present time. In this work, using first-principles calculations, a quantum qubit behavior based on a doped phosphorus atom in a Si lattice was theoretically investigated. The local magnetic field B(r), the local magnetization m(r), and the spin current density created by the excess electron from the phosphorus atom were calculated. It was shown that the P atom spin equilibrium orientation in the Bloch sphere corresponds to the following polar coordinates (θ; φ) = 176°; 102° and the |1⟩ quantum state. For the different |0⟩ and |1⟩ quantum states, there is a different direction of the spin current densities. The obtained novel results have a prospective significance for the design technology of future quantum computers.