Quantized zero-bias conductance plateau in semiconductor-superconductor heterostructures without topological Majorana zero modes

摘要

Recent observations of robust zero-bias quantized conductance plateaus of height 2e(2)/h in quantum dot-semiconductor-superconductor nanowire heterostructures have been interpreted as clear evidence for the presence of non-Abelian topologically protected Majorana zero modes (MZMs), since other sources of lowenergy conductance are believed to be unable to produce such quantized plateaus. Based on extensive numerical calculations, we show that, in fact, quantized conductance plateaus of height 2e(2)/h can also arise as a result of partially separated Andreev bound states (ps-ABSs), in which the component Majorana bound states are somewhat shifted in space without being topological MZMs. As ps-ABSs can form rather generically in the topologically trivial phase, even in the absence of disorder, our results conclusively establish that the observation of quantized conductance plateaus of height 2e(2)/h does not represent sufficient evidence for the existence of topologically protected MZMs localized at the opposite ends of a wire.