Electrically Switchable Entanglement Channel in van der Waals Magnets

Two-dimensional layered van der Waals (vdW) magnets demonstrate their potential to allow the study of both fundamental and applied physics due to their remarkable electronic properties. However, the connection of vdW magnets to spintronics and quantum information science is not clear. In particular, it remains elusive whether there are interesting magnetic phenomena belonging only to vdW magnets but absent in widely studied crystalline magnets. Here, we consider the quantum correlations of magnons in a layered vdW magnet and identify an entanglement channel of magnons across the magnetic layers, which can be effectively tuned and even deterministically switched on and off by both magnetic and electric means. This is a unique feature of vdW magnets, in which the underlying physics is well understood in terms of the competing roles of exchange and anisotropy fields that contribute to magnon excitation. Furthermore, we show that such a tunable entanglement channel can mediate the electrically controllable entanglement of two distant qubits, which also provides a protocol to indirectly measure the entanglement of magnons. Our findings provide an avenue to electrically manipulate qubits and further open up opportunities to utilize vdW magnets for quantum information science