Master's thesis presentation Karn Rongrueangkul

Supervisors: Alexei Kalaboukhov, Thilo Bauch
Examiner: Floriana Lombardi

Abstract: The normal states of cuprates high temperature superconductors (HTS) are characterized by multiple intertwined charge/spin orders, as reflected in the intricated electronic phase diagram. A strategy to advance the study of these complex materials is to tune the local orders by applying strain to the cuprates in nm thick films. Previously, it was discovered that the behaviours of a cuprate, namely YBa2Cu3O7-δ (YBCO), are dramatically modified due to the unidirectional strain when shrinking the material down to only a few unit-cell-thick. One of the changes is the resistivity behaviour which becomes highly anisotropic along the crystallographic directions. Such anisotropy is connected to the anisotropic Fermi surface. Consequently, the electron-phonon coupling (EPC) would become anisotropic as well. The focus of this thesis work is to investigate the anisotropic EPC through the study of electrical and heat transport properties of YBCO nanowires oriented along different crystallographic axes where the strain is tuned by changing the thickness of YBCO thin films.