Bottom-up grown nanowire quantum devices

A quantum computer can outperform classical computers for certain tasks. The general challenge to realize a quantum computer is to solve decoherence, which is due to coupling of a quantum state with the local environment. One possible way to overcome decoherence is to use a topological quantum state. Topologically protected states are expected to have long coherence times. In a topological quantum computer, the information is carried by nonlocal Majorana states. Such states can be engineered in a semiconductor nanowire, which has strong spin-orbit interactions, coupled to a superconductor. The first signatures of Majorana states have been observed recently. In order to substantiate the existence of Majorana states and use them as qubits, an exchange - or braiding - operation of these states has to be performed. The current challenge is to improve the quality of the materials and interfaces. Recent progress toward improved Majorana signals using materials science advances is reviewed in this article.