Dottorato in FISICA

Titolo della tesi: Strange-metal behavior of cuprates driven by dissipative charge collective modes

This work focuses on the study of high-temperature superconducting copper oxides, commonly known in the literature as "cuprates". Beyond high-temperature superconductivity, these systems are characterized by a complex phenomenology which shows considerable deviations from the standard theory of metals and whose comprehensive understanding is still an open problem in condensed matter theory. Within our discussion, we will analyze some of the most remarkable physical phenomena observed in the so-called "strange-metal phase" of cuprates, for which there is still no unanimously shared theory that can explain them exhaustively. In the description that we will propose, a central role is played by appropriate short-ranged charge collective modes, recently observed throughout the strange-metal phase thanks to the RIXS experiments. Under suitable hypotheses regarding the Landau damping to which these collective modes are subject, we will show that they are capable of inducing a strange-metal behavior in the systems in which they are present. A discussion on the strongly anisotropic properties observed in the metallic phase of some cuprate thin films is also included.