Emergence of coherence in the charge-density wave state of 2H-NbSe2

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.