Effect of irradiation-induced disorder on charge density waves in a homogeneous cuprate superconductor YBa2Cu4O8

Charge density wave (CDW) and pseudogap are two ubiquitous phenomena in the normal state of underdoped cuprates, yet their interplay and relation to superconductivity remain rather unclear. Recent RIXS measurements on a homogeneous cuprate YBa2Cu4O8 (Y124) revealed a sharp CDW transition different from all other cuprates and occurring at 200 K, coincident with its pseudogap temperature T*. The gradual CDW onset below T* in other cuprates is therefore attributed to chemical and electronic inhomogeneity. To further clarify the effects of disorder, we hereby propose a high-resolution Cu-L3 RIXS experiment on Y124 single crystals where disorder is introduced by electron irradiation. While our preliminary REXS data suggest a possible smearing of the CDW transition and signatures of charge density fluctuation (CDF) after irradiation, we believe that a complete RIXS study is required to nail down the crucial role of disorder in CDW formation and to systematically search for dynamic CDFs.