Tracing the origin of charge density waves in cuprates*

Since the discovery of the so-called pseudogap phenomenon in the 1990’s, the origin of the state properties of the underdoped cuprate high T_C superconductors have been intensively studied [1]. An important step towards the identification of the HTSC pairing mechanism was the discovery, that a charge density wave (CDW) exists in large parts of the underdoped phase diagram [2-5]. It was shown, that in zero magnetic field (B=0) the short-ranged, static CDW is induced by defects, while a long-range CDW can be induced for high B-fields along the c-axis (perpendicular to the CuO₂ layers).
Here we aim to search for the origin of this CDW, its role in the pseudogap phenomenology and its relationship with superconductivity (competing or interwined order). We performed reflection experiments from THz-NIR region (50cm^-1-6000cm^-1) while applying high magnetic fields up to B=30Tesla.

[1] B. Keimer, et al. Nature 518, 179 (2015)
[2] Tao Wu, et al. Nature 477, 191 (2011)
[3] S. Gerber, et al. Science 350, 949 (2015)
[4] G. Ghiringhelli, et al. Science 337, 821 (2012)
[5] J. Chang, et al. Nature Physics 8, 871 (2012)