Quantized spin pumping in topological ferromagnetic-superconducting nanowires

Abstract

Semiconducting nanowires with strong spin-orbit coupling in the presence of induced superconductivity and ferromagnetism can support Majorana zero modes. We study the pumping due to the precession of the magnetization in single-subband nanowires and show that spin pumping is robustly quantized when the hybrid nanowire is in the topologically nontrivial phase, whereas charge pumping is not quantized. Moreover, there exists one-to-one correspondence between the quantized conductance, entropy change and spin pumping in long topologically nontrivial nanowires but these observables are uncorrelated in the case of accidental zero-energy Andreev bound states in the trivial phase. Thus, we conclude that observation of correlated and quantized peaks in the conductance, entropy change and spin pumping would provide strong evidence of Majorana zero modes, and we elaborate how topological Majorana zero modes can be distinguished from quasi-Majorana modes potentially created by a smooth tunnel barrier at the lead-nanowire interface. Finally, we discuss peculiar interference effects affecting the spin pumping in short nanowires at very low energies.

Final version. Modifications in main text (5 pages) and new sections in supplement (11 pages)

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Cited by in corpus (4)

• Non-Hermitian Fermi-Dirac Distribution in Persistent Current Transport
• Nonequilibrium finite frequency resonances in differential quantum noise driven by Majorana interference
• Thermoelectric fluctuations of interfering Majorana bound states
• Fluctuation response of a minimal Kitaev chain in nonequilibrium states