Abstract
Using angle-resolved photoemission spectroscopy, we report on the direct observation of the energy gap in caused by the charge-density waves (CDW). The gap opens in the regions of the momentum space connected by the CDW vectors, which implies a nesting mechanism of CDW formation. In remarkable analogy with the pseudogap in cuprates, the detected energy gap also exists in the normal state () where it breaks the Fermi surface into “arcs,” it is nonmonotonic as a function of temperature with a local minimum at the CDW transition temperature (), and it forestalls the superconducting gap by excluding the nested portions of the Fermi surface from participating in superconductivity.
- Received 23 May 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.166402
©2009 American Physical Society