Direct observation of multiband charge density waves in NbTe2

The electronic structure of periodic lattice distortion (PLD) in ${\mathrm{NbTe}}₂$ was examined using low-temperature scanning tunneling spectroscopy and microscopy. The striped PLDs with $3\ifmmode\times\else\texttimes\fi{}1$ and $1\ifmmode\times\else\texttimes\fi{}\frac{9}{2}$ superstructures were characterized in real and reciprocal space. The simultaneous formation of momentum-specific suppressions in the spectral weight and phase shifts of the wavefront related to the superstructures were observed at multiple energies. These unusual energy dependencies are well agreed with the charge density waves (CDWs) formed in the multiband electronic structure of ${\mathrm{NbTe}}₂$. Fermi-surface nesting and reconstruction of the reciprocal lattice were suggested in developing the multiband CDWs in ${\mathrm{NbTe}}₂$.