Figure 1: Spin configuration and corresponding emergent magnetic field with monopole solution in MnGe.
From: Critical phenomena of emergent magnetic monopoles in a chiral magnet
(a) Spin orientation in a 2 × 2 × 2 magnetic unit cell. (b) Configuration of emergent monopoles (yellow dots) and antimonopoles (green dots) in a 1 × 1 × 1.5 magnetic unit cell corresponding to the green box in a, displayed with constant z planes (blue and pink planes). A stream of emergent field between a monopole and an antimonopole on the same z level is also exemplified (pink plane). (c) Hedgehog and antihedgehog spin arrangements n(r) realized in the spin structure of MnGe, which are regarded as quantized source (monopole; Qm=+1) and sink (antimonopole; Qm=−1) of emergent field b(r), respectively, acting on conduction electrons. (d–g) Monopoles’ and antimonopoles’ positions and their trajectories (yellow and green dots and lines) and distributions of emergent magnetic field under varying magnetic field applied along the z direction. Monopoles and antimonopoles collide at white dots (f) and pair annihilate at black dots (g). Three contours of emergent-field distribution, that is, regions with |bz|=10 and 2, and surfaces of green box of a with |bz|<0.1 are dyed according to strength and sign of bz—thicker colour for larger magnitude of bz, red and blue for positive and negative bz, respectively (d–g).
