Unconventional spin-intertwined charge density wave in magnetic phases of kagome metal GdTi₃Bi₄

The symmetry breaking density waves and their interplay with spin and charge are crucial for understanding the correlated electronic states in quantum materials. However, symmetry-breaking density waves involving simultaneous charge and spin modulations remain largely unexplored. Here, we report the unconventional spin-intertwined charge density wave in magnetic kagome metal GdTi₃Bi₄ by scanning tunneling spectroscopy. We observe a 3Q charge density wave that is incommensurate with the crystalline lattice in both periodicity and orientation and breaks all mirror and rotation symmetries. The CDW undergoes incommensurate-commensurate transitions in a magnetic field and 3Q-1Q transitions as a function of applied magnetic field and temperature. Remarkably, the quantum and thermal melting of the CDW exhibits a phase structure closely resembling the bulk magnetization phase diagram of GdTi₃Bi₄, which provides evidence for the observation and manipulation of spin-intertwined CDW as a bulk property. Our findings reveal the microscopic textures of the intricate magnetic phases with unconventional charge-spin coupling, and offer insights into a broad class of multi-components density wave formation in kagome and other correlated quantum materials.