  TaTe$_4$, a metallic charge-density wave (CDW) material discovered decades
ago, has attracted renewed attention due to its rich interesting properties
such as pressure-induced superconductivity and candidate non-trivial
topological phase. Here, using high-resolution angle-resolved photoemission
spectroscopy and ab-initio calculation, we systematically investigate the
electronic structure of TaTe$_4$. At 26 K, we observe a CDW gap as large as 290
meV, which persists up to 500 K. The CDW-modulated band structure shows a
complex reconstruction that closely correlates with the lattice distortion.
Inside the CDW gap, there exist highly dispersive energy bands contributing to
the remnant Fermi surface and metallic behavior in the CDW state.
Interestingly, our ab-initio calculation reveals that the large CDW gap mainly
opens in the electronic states with out-of-plane orbital components, while the
in-gap metallic states originate from in-plane orbitals, suggesting an orbital
texture that couples with the CDW order. Our results shed light on the
interplay between electron, lattice, and orbital in quasi-one-dimensional CDW
materials.
