Majorana modes are zero-energy excitations of a topological superconductor that exhibit non-Abelian statistics^1,2,3. Following proposals for their detection in a semiconductor nanowire coupled to an s-wave superconductor^4,5, several tunnelling experiments reported characteristic Majorana signatures^{6,7,8,9,10,11}. Reducing disorder has been a prime challenge for these experiments because disorder can mimic the zero-energy signatures of Majoranas^{12,13,14,15,16}, and renders the topological properties inaccessible^17,18,19,20. Here, we show characteristic Majorana signatures in InSb nanowire devices exhibiting clear ballistic transport properties. Application of a magnetic field and spatial control of carrier density using local gates generates a zero bias peak that is rigid over a large region in the parameter space of chemical potential, Zeeman energy and tunnel barrier potential. The reduction of disorder allows us to resolve separate regions in the parameter space with and without a zero bias peak, indicating topologically distinct phases. These observations are consistent with the Majorana theory in a ballistic system²¹, and exclude the known alternative explanations that invoke disorder^{12,13,14,15,16} or a nonuniform chemical potential^22,23.

马约拉纳模式是拓扑超导体的零能量激发，表现出非阿贝尔统计^1,2,3 。在提出在与 s 波超导体耦合的半导体纳米线中进行检测^4,5后，一些隧道实验报告了特征马约拉纳特征^{6,7,8,9,10,11} 。减少无序性一直是这些实验的主要挑战，因为无序性可以模仿马约拉纳的零能量特征^{12,13,14,15,16} ，并使拓扑特性变得难以接近^17,18,19,20 。在这里，我们展示了 InSb 纳米线器件中的特征马约拉纳特征，表现出清晰的弹道输运特性。应用磁场和使用局域栅对载流子密度进行空间控制会产生零偏置峰值，该零偏置峰值在化学势、塞曼能量和隧道势垒势的参数空间中的大范围内是刚性的。无序度的减少使我们能够解析参数空间中具有和不具有零偏差峰值的单独区域，这表明拓扑上不同的相。这些观察结果与弹道系统中的马约拉纳理论²¹一致，并且排除了引起无序^{12,13,14,15,16}或不均匀化学势^22,23的已知替代解释。