Plasmon-induced magnetization in the edges of higher Chern insulators

This work theoretically discusses the collective behavior (plasmons) of chiral edge modes in higher Chern (hC) insulators, which have large Chern numbers. In the bulk, hC insulators have a band gap and quantized Hall conductivity according to the Chern number, C. In the edge, it has C number of chiral modes. Similar to edge plasmons in normal metals, oscillating chiral modes' self-generated potential can produce a circularly polarized electric field. The electric field then drives the electron in a circular fashion inducing an orbital magnetic moment, known as the inverse Faraday effect. This orbital motion will split spin up and spin down states allowing the spintronics application from edge plasmon. According to previous formalism, the magnetization is proportional to square of electric field and inversely proportional to charge density. In hC plasmons, the self-generated electric field will increase with the number of chiral edge channels and bulk density can be very small thus, we can expect a large enhancement of the induced magnetization. Moreover, the hc plasmons dispersion is largely linear in contrast to √q behavior of 2D edge plasmons and tunable by dielectric constant and band gap. The results will allow interesting opto-electronic applications using hC materials.