The distinction between the conduction band and the valence band is a fundamental concept in semiconductor physics, routinely referenced in studies measuring band edges, density of states, and electronic transitions. Multiple scientific studies independently confirm and analyze these two separate electronic bands.
The claim states that the conduction band is distinct from the valence band in materials. This is a foundational, well-established physical principle of solid-state electronics and semiconductor physics. All relevant retrieved papers explicitly treat the conduction band and valence band as distinct entities, measuring, calculating, or manipulating their respective edges, densities of states, or offsets. Thus, the evidence overwhelmingly supports the claim.