Photocurrent as a new lens for probing low-dimensional topological materials

Topological materials, characterized by unique quantum states and nontrivial band topologies, have become a central focus in physics due to their remarkable quantum and geometric properties. Over recent decades, extensive research has uncovered a diverse range of phenomena in these materials, from robust surface states and unconventional transport behaviours to extraordinary optical signatures. In this review, we first provide an overview of recent studies on topological materials and their associated quantum properties. We then examine the distinctive optical signatures that emerge from the quantum geometry of Bloch bands, manifesting as enhanced photocurrents and nonlinear optical effects. By linking these photocurrent characteristics to the intrinsic properties of topological materials, we aim to deepen the understanding of how band topology influences optical responses. Finally, we discuss the emerging opportunities enabled by topological quantum effects for next-generation optoelectronic and photonics devices and outline key challenges that must be addressed to fully leverage these effects in practical applications.