Long-range magnetic bounds states in ferromagnetic superconducting nanodiamond

June 22, 2020

Confronted with the needs of the ongoing revolution in quantum computing, fully different physical properties are combined to explore exotic electronic excitations for overcoming the limits of conventional states of condensed matter. When magnetic atoms are introduced into a superconductor, the local magnetic moments will destroy the local superconductivity, giving rise to magnetic bound states (MBS) in the superconducting gap. Such MBS can be used to create topologically protected qubits for quantum computers.

It was theoretically argued that the spatial extent of MBS is strongly dependent on the dimensionality of the hosting superconductor. In the case of a three-dimensional superconductor, the MBS should be limited to only a few atoms. Short-ranged MBS set obstacles in the path towards their applications.

Recently, an international research team led by our D-IAS Assistant Professor Gufei Zhang, discovered long-range MBS in a three-dimensional ferromagnetic superconductor, hydrogenated boron-doped nanodiamond [G. Zhang et al. Sci. Adv. 6, eaaz2536 (2020); G. Zhang et al. ACS Nano 11, 5358 (2017)]. The observed MBS extend up to tens of nanometers, revealing the delocalization of the in-gap electronic excitations. These new findings raise intriguing questions in quantum physics and provide promising building blocks for quantum electronics.