Abstract: Under certain conditions, a fermion in a superconductor can separate in space into two parts known as Majorana zero modes, which are immune to decoherence from local noise sources and are attractive building blocks for quantum computers. Here we disclose a metal-based heterostructure platform to produce these Majorana zero modes which utilizes the surface states of certain metals in combination with a ferromagnetic insulator and a superconductor. This platform has the advantage of having a robust energy scale and the possibility of realizing complex circuit designs using lithographic methods. The Majorana zero modes are interrogated using planar tunnel junctions and electrostatic gates to selectively tunnel into designated pairs of Majorana zero modes. We give example of qubit designs and circuits that are particularly suitable for the metal-based heterostructures.

Abstract: Under certain conditions, a fermion in a superconductor can separate in space into two parts known as Majorana zero modes, which are immune to decoherence from local noise sources and are attractive building blocks for quantum computers. Here we disclose a metal-based heterostructure platform to produce these Majorana zero modes which utilizes the surface states of certain metals in combination with a ferromagnetic insulator and a superconductor. This platform has the advantage of having a robust energy scale and the possibility of realizing complex circuit designs using lithographic methods. The Majorana zero modes are interrogated using planar tunnel junctions and electrostatic gates to selectively tunnel into designated pairs of Majorana zero modes. We give example of qubit designs and circuits that are particularly suitable for the metal-based heterostructures.

Abstract: The generation of photocurrent in an ideal two-dimensional Dirac spectrum is symmetry forbidden. In sharp contrast, a three-dimensional Weyl semimetal can generically support significant photocurrent due to the combination of inversion symmetry breaking and finite tilts of the Weyl spectrum. To realize this photocurrent, a noncentrosymmetric Weyl semimetal is coupled to a pair of electrodes and illuminated with circularly polarized light without any voltage applied to the Weyl semimetal. The wavelength of the incident light can range over tens of microns and can be adjusted by doping the Weyl semimetal to change its chemical potential.

Abstract: The generation of photocurrent in an ideal two-dimensional Dirac spectrum is symmetry forbidden. In sharp contrast, a three-dimensional Weyl semimetal can generically support significant photocurrent due to the combination of inversion symmetry breaking and finite tilts of the Weyl spectrum. To realize this photocurrent, a noncentrosymmetric Weyl semimetal is coupled to a pair of electrodes and illuminated with circularly polarized light without any voltage applied to the Weyl semimetal. The wavelength of the incident light can range over tens of microns and can be adjusted by doping the Weyl semimetal to change its chemical potential.