报告时间：9月20日 周三  下午2:30

报告地点：实验室一楼会议室

报告人：吴从军教授(UCSD)

报告题目： Septet topological superconductivity and surface Majorana modes

报告摘要：

We systematically generalize the exotic  $^3$He-B phase, which not only exhibits unconventional symmetry but is also isotropic and topologically nontrivial, to electronic systems with multi-orbital band structures (e.g. half-heusler compounds). For example, the 4-component, i.e., effectively spin-$\frac{3}{2}$, electronic systems can support spin septet and triplet topological superconductivities, and their surface Majorana spectra exhibit multiple linear and even high order Dirac cones. We also identify the mixing between spin triplet and singlet superconductivity leads to a novel mechanism of time-reversal symmetry breaking superconductivity. For the Majorana edge modes of quantum wires, we study whether these zero modes can persist in an array of coupled wires, and if not, what their remnant might be. The bulk exhibits topologically distinct gapped phases and an intervening gapless phase. The interaction between Majorana zero modes and superfluid phases leads to spontaneous time-reversal symmetry breaking. Consequently, edge supercurrent loops emerge and edge Majorana fermions can be gapped out.

References：

[1] Wang Yang, Yi Li, C. Wu, “Topological septet pairing with spin-3/2 fermions -- high partial-wave channel counterpart of the $^3$He-B phase”, Phys. Rev. Lett. 117, 075301(2016).
[2] C. Wu, J. E. Hirsch, “Mixed triplet and singlet pairing in ultracold multicomponent fermion systems with dipolar interactions”, Phys. Rev. B 81, 020508 (R) (2010).
[3] Yi Li, Da Wang, C. Wu, “Spontaneous time-reversal symmetry breaking in the boundary Majorana flat bands,” New J. Phys. 15 085002 (2013).
[4] Yi Li, C. Wu, "The J-triplet Cooper pairing with magnetic dipolar interactions", Scientific Report 2, 392 (2012).

编辑时间：2017-09-15 10:04:49