Researchers in the Center for Quantum Materials Science, School of Physics at Georgia Tech have achieved a major breakthrough. In particular, they have advanced our understanding of non-reciprocal Coulomb drag amongst Chern Insulators. He Qinglin was the lead author of this pioneering study, which represented the first observation of such phenomena in magnetic topological materials. Our findings are described in a study recently published in Nature Communications.
Chern Insulators have extraordinary properties. In highly frustrated lattices, they can show a quantized Hall effect even in the absence of external magnetic fields. This unique feature is a result of intrinsic magnetization and emergence of chiral edge states. Recent experimental discoveries of Chern Insulators have illustrated the promise of this field. They can act as compelling platforms to study non-reciprocal quantum transport phenomena, which can impact technological applications to come.
The research team, including authors Yu Fu et al., conducted experiments at ultra-low temperatures of 20 mK while applying perpendicular magnetic fields. This particular configuration proved crucial for probing the nature of QAH effect (QAH) transitions. The results revealed that Coulomb drag occurs when a current in one conductor induces a measurable voltage in a nearby electrically insulated conductor through long-range Coulomb interactions.
These results represent a first observation of non-reciprocal Coulomb drag in a Chern Insulator by researchers. This exciting realization provides a whole new avenue for probing exotic quantum transport phenomena. At these lower temperatures, mesoscopic fluctuations come to the forefront. They show T² scaling, which is important for explaining the low-temperature behavior of Chern Insulators. Additionally, shot noise was found at larger bias values, adding to the nonlinear behavior seen in these materials.
