Two energy gaps and Fermi surface 'arcs' in NbSe2

Abstract

Using angle-resolved photoemission spectroscopy (ARPES), we report on the direct observation of the energy gap in 2H-NbSe2 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 (T>T0) where it breaks the Fermi surface into 'arcs', it is non-monotonic as a function of temperature with a local minimum at the CDW transition temperature (T0) and it forestalls the superconducting gap by excluding the nested portions of the Fermi surface from participating in superconductivity.

Related work http://www.ifw-dresden.de/institutes/iff/research/SC/arpes

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Cited by in corpus (1)

• Momentum-resolved superconducting gap in the bulk of Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ from combined ARPES and $\mu$SR measurements