LOW-FIELD ANOMALY IN 2D HOPPING MAGNETORESISTANCE CAUSED BY SPIN-ORBIT TERM IN THE ENERGY-SPECTRUM

We demonstrate that a k-linear spin-orbit term (H) over cap(so) in the Hamiltonian of a 2D electron, causing a minimum in the energy spectru m at finite k = k(0), changes the low-field dependence of magnetoresis tance from delta R(B) alpha -\B\ to delta R(B) alpha -1/2(\B - B-0\ \B + B-0\ - 2B(0)), where B-0 = k(0)(2) Phi(0)/pi is an effective fiel d generated by (H) over cap(so). The anomaly is suppressed by orientin g electron spins in the plane with a strong parallel magnetic field.