@article{a2368c65afad4297b03493855629db54,
title = "Emergence of coherence in the charge-density wave state of 2H-NbSe2",
abstract = "A charge-density wave (CDW) state has a broken symmetry described by a complex order parameter with an amplitude and a phase. The conventional view, based on clean, weak-coupling systems, is that a finite amplitude and long-range phase coherence set in simultaneously at the CDW transition temperature Tcdw. Here we investigate, using photoemission, X-ray scattering and scanning tunnelling microscopy, the canonical CDW compound 2H-NbSe2 intercalated with Mn and Co, and show that the conventional view is untenable. We find that, either at high temperature or at large intercalation, CDW order becomes short-ranged with a well-defined amplitude, which has impacts on the electronic dispersion, giving rise to an energy gap. The phase transition at Tcdw marks the onset of long-range order with global phase coherence, leading to sharp electronic excitations. Our observations emphasize the importance of phase fluctuations in strongly coupled CDW systems and provide insights into the significance of phase incoherence in 'pseudogap' states.",
author = "U. Chatterjee and J. Zhao and M. Iavarone and {Di Capua}, R. and Castellan, {J. P.} and G. Karapetrov and Malliakas, {C. D.} and Kanatzidis, {M. G.} and H. Claus and Ruff, {J. P.C.} and F. Weber and {Van Wezel}, J. and Campuzano, {J. C.} and R. Osborn and M. Randeria and N. Trivedi and Norman, {M. R.} and S. Rosenkranz",
note = "Funding Information: Work at Argonne (U.C., J.Z., J.P.C., C.D.M., M.G.K., H.C., J.P.C.R., F.W., J.C.C, R.O., M.R.N., S.R.) was supported by the Materials Science and Engineering Division, Basic Energy Sciences, Office of Science, U.S. Department of Energy. Work at Temple University (M.I) and Drexel University (G.K.) was supported as part of the Center for the Computational Design of Functional Layered Materials, an Energy Frontier Research Center funded by the U.S. DOE, BES under Award DE-SC0012575. J.v.W. acknowledges support from a VIDI grant financed by the Netherlands Organization for Scientific Research (NWO). M.R. was supported by the DOE-BES grant DE-SC0005035. N.T. was supported by the U.S. DOE, Office of Science, Grant DE-FG02-07ER46423. The Synchrotron Radiation Center is supported by the University of Wisconsin, Madison. Synchrotron X-ray scattering experiments were carried out at the Advanced Photon Source, which is supported by the DOE, Office of Science, BES. We thank Ming Shi for his support with the experiments at the Swiss Light Source, Paul Scherrer Institut, Switzerland, and D. Robinson and K. Attenkofer for their support with the XRD measurements at the Advanced Photon Source, Argonne National Laboratory. Publisher Copyright: {\textcopyright} 2015 Macmillan Publishers Limited. All rights reserved.",
year = "2015",
month = feb,
day = "17",
doi = "10.1038/ncomms7313",
language = "English",
volume = "6",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
}