Tunable RKKY interaction in 30° twisted bilayer graphene

By means of the Lanczos method, we study the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in 30 degrees twisted bilayer graphene (TBG). We find that the RKKY interaction in 30 degrees TBG is identical to the counterpart in monolayer graphene, i.e., it conforms with the R-3 decay rate and Saremi's rule holds. Then we study the RKKY interaction mediated by the carriers of the biased 30 degrees TBG as well as the conduction electrons of the doped system. This RKKY interaction oscillates between ferromagnetic (FM) and antiferromagnetic (AFM) as the distance R between two magnetic impurities increases, and a long-range behavior of the R-2 decay rate is established. Moreover, we also find that the strength and sign of the RKKY interaction in the 30 degrees TBG can be readily controlled by altering the gate voltage or carrier doping. By means of the Lanczos method, we study the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in 30 degrees twisted bilayer graphene (TBG).