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arXiv · 0904.3277

Two energy gaps and Fermi surface 'arcs' in NbSe2

S. V. Borisenko·A. A. Kordyuk·V. B. Zabolotnyy·D. S. Inosov·D. Evtushinsky·B. Buechner·A. N. Yaresko·A. Varykhalov·R. Follath·W. Eberhardt·L. Patthey·H. Berger
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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.

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S. V. Borisenko, A. A. Kordyuk, V. B. Zabolotnyy, D. S. Inosov, D. Evtushinsky, B. Buechner, A. N. Yaresko, A. Varykhalov, R. Follath, W. Eberhardt, L. Patthey, H. Berger. 2009-04-21. Two energy gaps and Fermi surface 'arcs' in NbSe2. https://doi.org/10.1103/physrevlett.102.166402

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