Correlation-driven nonlinear transport in centrosymmetric FeTe

Quantum geometry parameter induces rich physical properties, and nonlinear transport provides a method to sense it. Among different higher-order terms in quantum geometry, 3rd-order transport serves as a general path for touching band topology even for highly symmetric materials¹. Moreover, as non-interacting systems already succeeded in nonlinear transport², correlation effects are promising for efficiently controlling nonlinear transport³. In this work, we report 3^rd order nonlinear transport in FeTe. At low temperature, we observe the sizable 3^rd-order itinerant electron motion nonlinearity with a two-fold angular dependence, following local spin texture. At high temperatures, 3^rd order nonlinear signal drops quickly. Through the scaling analysis, we determine the origin to be quantum metric quadrupole and conclude a finite energy gap opening at low temperature. The disappearance of QMQ and energy gap is determined to be a result of coherent-incoherent crossover caused by Hund’s coupling⁴. At coherent state, a Kondo-like correlation results in the hybridization of Fe orbital and other itinerant orbitals⁵. When increasing temperature, no hybridization and no nontrivial quantum geometry survives as there’s no sizeable nonlinear transport. Our work highlights a correlation-driven nonlinear transport and advances an efficient modulation method of quantum metric quadrupole relying on correlation effect.