Effect of uniaxial stress on the magnetic phases of CeAuSb₂

We present results of measurements of resistivity of CeAuSb2 under the combination of c-axis magnetic field and in-plane uniaxial stress. In unstressed CeAuSb2 there are two magnetic phases. The low-field A phase is a single-component spin-density wave (SDW), with q = (eta, +/-eta, 1/2), and the high-field B phase consists of microscopically coexisting (eta, eta, 1/2) and (eta, -eta, 1/2) spin-density waves. Pressure along a lattice direction is a transverse field to both of these phases and so initially has little effect, however it eventually induces new low-and high-field phases in which the principal axes of the SDW components appear to have rotated to the directions. Under this strong compression, the field evolution of the resistivity is much smoother than at zero strain: In zero strain, there is a strong first-order transition, while under strong it becomes much broader. We hypothesize that this is a consequence of the uniaxial stress lifting the degeneracy between the (100) and (010) directions