Pair density waves with different orientations revealed by Andreev reflection spectra

Wan-Ju Li^1*, Yi-Hsuan Liu¹, Ting-Kuo Lee^1,2

¹Department of Physics, National Tsing-Hua University, Hsinchu, Taiwan
²Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Wan-Ju Li, email:wanjuli@phys.nthu.edu.tw

The pair density wave (PDW) state is recently proposed to be present in high temperature superconductors. Although there are several experimental evidences to support such a proposal, a direct evidence that depends on the unique property of PDW state is still lacking. In this work we propose to detect the PDW states by probing the Andreev reflection from the metal/insulator/PDW states junction. The angular and energy dependence of the transport property of this heterostructure is calculated by using BTK formalism in lattice models. Two distinct geometries are studied: the first (second) one contains a PDW modulation parallel (perpendicular) to the interface and is denoted as PDW-y (PDW-x). Nearly degenerate ground states, from self-consistent calculations of t-J models, such as APCDW and commensurate PDW with a node (nodal PDW), are examined for both geometries. The differences among the PDW-x, PDW-y and usual BCS systems are discussed. These unique new features could be used to verify the existence of the PDW in cuprates.

Keywords: pair density wave, Andreev reflection, BTK, cuprate