Review: Observation of Majorana Bound States at a Free Surface of He-3-B

Hiroki Ikegami*, Kimitoshi Kono

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The p-wave superfluid 3He is a textbook example of topological superfluids. Among its multiple superfluid phases, the B phase (3He-B) is known as a topological state protected by time-reversal symmetry. One of the important topological features of 3He-B is the formation of bound states at its surface. Notably, such surface Andreev bound states are predicted to be Majorana fermions, i.e., their antiparticles are identical to their particles. Because of the well-elucidated bulk properties of the superfluid 3He owing to its cleanliness, 3He-B provides an ideal platform to pursue Majorana fermions in condensed matter systems. In this article, we review recent investigations of surface Andreev bound states by the mobility of ions trapped below a free surface of 3He-B. The free surface is an ideal surface providing a specular boundary condition; the surface Andreev bound states formed there are expected to be Majorana fermions with a well-defined energy spectrum. We show that the temperature and depth dependences of the experimentally obtained mobility of negative ions (Ikegami et al. in J Phys Soc Jpn 82:124607, 2013) are quantitatively reproduced by a theoretical study that includes scattering of the surface Andreev bound states (Tsutsumi in Phys Rev Lett 118:145301, 2017). This quantitative agreement unambiguously demonstrates the experimental detection of surface Andreev bound states. We also discuss the future prospects of the Majorana physics in He-3-B.

Original languageEnglish
Pages (from-to)343-357
Number of pages15
JournalJournal of Low Temperature Physics
Volume195
Issue number3-4
DOIs
StatePublished - May 2019
EventInternational Workshop on Electrons and Ions in Quantum Fluids and Solids - Mishima, Japan
Duration: 12 Mar 201814 Mar 2018

Keywords

  • Majorana fermion
  • Topological superfluid
  • Superfluid He-3
  • Surface Andreev bound states
  • Ion
  • NONLINEAR TRANSPORT
  • SUPERFLUID HE-3-B
  • QUASI-PARTICLES
  • NEGATIVE-IONS
  • ZERO MODES
  • FERMIONS
  • MOBILITY
  • SUPERCONDUCTOR
  • SIGNATURE
  • BREAKING

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