Unconventional spin-intertwined charge density wave in magnetic phases of kagome metal GdTi(3)Bi(4).

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 GdTiBi 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 GdTiBi, 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.