NMR-like effect on the anisotropic magnetic moment of surface bound states in the topological superfluid He3−B

Abstract

We present experimental observation of a phenomenon that we interpret as a NMR-like effect on an anisotropic magnetic moment of the surface Andreev bound states in topological superfluid $^{3}\mathrm{He}\text{\ensuremath{-}}\mathrm{B}$ at zero temperature limit. We show that an anisotropic magnetic moment formed near the horizontal surface of a mechanical resonator due to symmetry violation of the superfluid $^{3}\mathrm{He}\text{\ensuremath{-}}\mathrm{B}$ order parameter by the resonator's surface may lead to anomalous damping of the resonator motion in magnetic field. In difference to the classical NMR technique, here NMR was excited using own harmonic motion of the mechanical resonator and nuclear magnetic resonance was detected as a maximum in damping when the resonator's angular frequency satisfied the Larmor resonance condition.