Orbital selective commensurate modulations of the local density of states in ScV6Sn6 probed by nuclear spins

The Kagome network is a unique platform in solid state physics that harbors a diversity of special electronic states due to its inherent band structure features comprising Dirac cones, van-Hove singularities, and flat bands. Some Kagome-based non-magnetic metals have recently been found to exhibit favorable properties, including unconventional superconductivity, charge density waves (CDW), switchable chiral transport, and signatures of an anomalous Hall effect (AHE). The Kagome metal ScV6Sn6 is another promising candidate for studying the emergence of an unconventional CDW and accompanying effects. We use 51V nuclear magnetic resonance (NMR) to study the local properties of the CDW phase in single crystalline ScV6Sn6, aided by density functional theory (DFT). We trace the dynamics of the local magnetic field during the CDW phase transition and determine a loss in the density of states (DOS) by a factor of $\sqrt{2}$, in excellent agreement with DFT. The local charge symmetry of the V surrounding in the CDW phase reflects the commensurate modulation of the charge density with wave vector q=(1/3,1/3,1/3). An unusual orientation dependent change in the NMR shift splitting symmetry, however, reveals orbital selective modulations of the local DOS.
Comment: 25 pages, 6 figures, supplementary files