Ground-state angular momentum, spectral asymmetry, and topology in chiral superfluids and superconductors | |
Article | |
关键词: HE-3-A; PHASE; LIQUID-HE-3; | |
DOI : 10.1103/PhysRevB.93.174505 | |
来源: SCIE |
【 摘 要 】
Recently, it was discovered that the ground-state orbital angular momentum in two-dimensional chiral superfluids with pairing symmetry (px + ipy)(nu) depends on the winding number nu in a striking manner. The ground-state value for the nu = 1 case is L-z = (h) over barN/2 as expected by counting the Cooper pairs, while a dramatic cancellation takes place for nu > 1. The origin of the cancellation is associated with the topological edge states that appear in a finite geometry and give rise to a spectral asymmetry. Here, we study the reduction of orbital angular momentum for different potential profiles and pairing strengths, showing that the result L-z = (h) over barN/2 is robust for nu = 1 under all studied circumstances. We study how angular momentum depends on the gap size Delta/E-F and obtain the result L-z = (h) over bar nu/2N(1 -mu/E-F) for nu = 2,3. Thus, the gap dependence of L-z for nu < 4 enters at most through the chemical potential while nu >= 4 is qualitatively different. In addition, we generalize the spectral asymmetry arguments to total angular momentum in the ground state of triplet superfluids where due to a spin-orbit coupling L-z is not a good quantum number. We find that the ground-state total angular momentum also behaves very differently depending on total angular momentum of the Cooper pairs.
【 授权许可】
Free