Phys.org December 16, 2022
Hybrid semiconductor–superconductor devices hold great promise for realizing topological quantum computing with Majorana zero modes. However, multiple claims of Majorana detection, based on either tunnelling or Coulomb blockade (CB) spectroscopy, remain disputed. An international team of researchers (Austria, USA – Princeton University, Spain) devised an experimental protocol that allowed them to perform both types of measurement on the same hybrid island by adjusting its charging energy via tunable junctions to the normal leads. This method reduces ambiguities of Majorana detections by checking the consistency between CB spectroscopy and zero-bias peaks in non-blockaded transport. They observed junction-dependent, even–odd modulated, single-electron CB peaks in InAs/Al hybrid nanowires without concomitant low-bias peaks in tunnelling spectroscopy. They provided a theoretical interpretation of the experimental observations in terms of low-energy, longitudinally confined island states rather than overlapping Majorana modes. According to the researchers their results highlight the importance of combined measurements on the same device for the identification of topological Majorana zero modes…read more. TECHNICAL ARTICLE
Looking for the Majorana rock star. Images. Credit: Maksim Borovkov