Electron hole complementary spatial texturing of the charge order in a doped commensurate charge density wave.
The charge density wave (CDW) ground state has been studied extensively, but its formation mechanism and interplay with superconductivity remain matter of intense experimental and theoretical scrutiny. It is commonly assumed that the CDW involves Fermi surface nesting with a gap opening at the Fermi level (EF), therefore competing with superconductivity, and suppressing the charge ordered phase is among proposed avenues to achieve higher superconducting transition temperatures1. Here, using scanning tunneling microscopy, we find that the CDW gap is opening below EF in 1T-CuxTiSe2. It shifts to even higher binding energies with increasing Cu doping, resulting in a unique energy dependent CDW patchwork spanning complementary regions at positive and negative bias in real space. Most remarkably, we observe clear charge order for Cu doping deep inside the superconducting phase, questioning a simple competition between charge ordering and superconductivity.
Publisher URL: http://arxiv.org/abs/1710.04096