InAs-Al hybrid devices passing the topological gap protocol

On the conclusive detection of Majorana zero modes: conductance spectroscopy, disconnected entanglement entropy and the fermion parity noise

“…The three terminal N-TS-N setup [25,29,30] that we consider is shown in figure 1(a). The setup comprises a semiconducting nanowire (in blue) with strong Rashba type spin-orbit coupling with an epitaxial layer of s-wave superconductor (in purple), placed in contact with metallic leads 'L' and 'R' (in pink).…”

“…The non-local differential conductance probes the bulk-gap closing and reopening and is presumed to be uninfluenced by the trivial modes [23]. Ideas proposing measurements of the full conductance matrix, which includes both local and non-local measurements, to identify topological regimes have also been presented [29,30]. Nonetheless, numerical [28,31] and experimental [25] studies have portrayed several issues with the non-local conductance signatures as well, with the signals becoming faint and sputtered [28] accompanied by a premature gap closing [25,31] in the presence of disorders.…”

Dimensionality effects on trap-assisted recombination: the Sommerfeld parameter

“…Going further, semiconductor nanowires, in which confinement of carriers leads to quasi-one-dimensional behavior, are being explored for next-generation optoelectronic devices [15]. Semiconductor nanowires [16] and gate-defined quasi-onedimensional wires derived from a two-dimensional electron gas [17] have been employed in the search for Majorana bound states. Devices are getting ever smaller, and quantum effects and dimensionality play a larger role.…”

Ballistic PbTe Nanowire Devices

“…A clean semiconductor nanowire coupled to a superconductor has been predicted to host Majorana zero modes. , Despite the tremendous effort that has been devoted to reducing disorder in InAs and InSb nanowire devices, − all of the Majorana nanowire experiments − still suffer from disorder. Take, for instance, the four recent studies: the observation of quantized zero-bias peaks in a thin InAs-Al nanowire, simulating a Kitaev chain using two quantum dots coupled to a superconductor, the topological-gap-protocol devices based on three-terminus InAs-Al, and the zero-bias peaks in phase-tunable planar Josephson junctions . All of these studies have used a gate-tunable quantum point contact (QPC) as the probe.…”