{"id":59742,"date":"2025-04-29T08:37:06","date_gmt":"2025-04-29T08:37:06","guid":{"rendered":"https:\/\/www.europesays.com\/uk\/59742\/"},"modified":"2025-04-29T08:37:06","modified_gmt":"2025-04-29T08:37:06","slug":"first-observation-of-non-reciprocal-coulomb-drag-in-chern-insulators-reported","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/uk\/59742\/","title":{"rendered":"First observation of non-reciprocal Coulomb drag in Chern insulators reported"},"content":{"rendered":"

\"First<\/p>\n

Device and Coulomb drag from Chern insulator. Credit: Nature Communications (2025). DOI: 10.1038\/s41467-025-58401-5<\/p>\n

He Qinglin’s group at the Center for Quantum Materials Science, School of Physics, has reported the first observation of non-reciprocal Coulomb drag in Chern insulators. This breakthrough opens new pathways for exploring Coulomb interactions in magnetic topological systems and enhances our understanding of quantum states in such materials. The work was published<\/a> in Nature Communications.<\/p>\n

Coulomb drag<\/a> arises when a current in one conductor induces a measurable voltage in a nearby, electrically insulated conductor via long-range Coulomb interactions.<\/p>\n

Chern insulators are magnetic topological materials that show a quantized Hall effect without external magnetic fields<\/a>, due to intrinsic magnetization and chiral edge states.<\/p>\n

The research marks the first foray into non-reciprocal Coulomb drag in a magnetic Chern insulator, which has long remained uncharted territory. It offers insights into topological quantum materials, revealing new aspects of quantum fluctuations and interactions. The study also advances topological quantum computing by providing a non-contact detection method for quantum states (relevant for qubits).<\/p>\n

The researchers used a Molecular Beam Epitaxy (MBE) grown V-doped (Bi,Sb)\u2082Te\u2083 optimized for the high-temperature quantum anomalous Hall (QAH) effect, along with a Dual Hall bar with nanoscale vacuum gap to ensure pure Coulomb coupling (no tunneling). Ultra-low temperature (20 mK) and perpendicular magnetic fields were used to explore quantum anomalous Hall effect (QAH) transitions.<\/p>\n

The researchers measured longitudinal (V\u2093\u2093) and transverse (V\u2093\u1d67) drag voltages; I-V curves (to distinguish shot noise vs. fluctuation regimes); and temperature\/power-law scaling (to confirm mesoscopic origin).<\/p>\n

Key findings include:<\/p>\n