Absence of zero-energy surface bound states in CuxBi 2Se3 studied via Andreev reflection spectroscopy

Haibing Peng, Debtanu De, Bing Lv, Fengyan Wei, Ching Wu Chu

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47 Citations (Scopus)

Abstract

CuxBi2Se3 has been proposed as a potential topological superconductor characterized by an odd-parity full bulk superconducting gap and zero-energy surface Andreev bound states (Majorana fermions). A predicted consequence of such Majorana fermions is a peak in the zero-energy density of states, which should lead to a persistent zero bias conductance peak (ZBCP) in Andreev reflection (AR) or tunneling experiments. Here, we employ a newly developed nanoscale AR spectroscopy method to study normal metal/superconductor (N-S) devices featuring CuxBi 2Se3. The results show that a ZBCP can be tuned in or out from CuxBi2Se3 samples depending on the N-S barrier strength. While the appearance of ZBCP may be traced to different origins, its absence under finite barrier strength represents the absence of zero-energy Majorana fermions. The present observations thus call for a reexamination of the intriguing superconductivity in CuxBi 2Se3.

Original languageEnglish
Article number024515
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume88
Issue number2
DOIs
Publication statusPublished - 2013 Jul 25

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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