Antiferromagnetic order in a semiconductor quantum well with spin–orbit coupling

An argument is made on the existence of a low-temperature itinerant antiferromagnetic (AF) spin alignment, rather than persistent helical (PH), in the ground state of a two dimensional electron gas in a semiconductor quantum well with linear spin–orbit Rashba–Dresselhaus interaction at equal coupling strengths, α  . This result is obtained on account of the opposite-spin single-particle state degeneracy at k=0k=0 that makes the spin instability possible. A theory of the resulting magnetic phase is formulated within the Hartree–Fock approximation of the Coulomb interaction. In the AF state the direction of the fractional polarization is obtained to be aligned along the displacement vector of the single-particle states.