Complex oxide heterostructures for novel topological superconducting states
Abstract
Superconductivity is one of most fascinating emergent states of matter with unparalleled electromagnetic properties that could be exploited for a wide range of technological applications from electronics to quantum information. While its discovery was more than one hundred years ago, its potential impact acquires a new dimension upon the recent development of topological states of matter. The possibility of combining superconductivity and symmetry-protected fermionic states has led to the concept of topological superconductors and a variety of theoretically predicted realizations, especially the use of heterojunctions. However, attentions have been focused on utilizing s-wave pairing often found in conventional superconductors rather than dwave pairing that occurs in high-temperature superconducting cuprates. The main barrier stems from the complex pairing mechanism due to the correlated physics of high-temperaturesuperconductivity and the lack of experimentally identified topological oxide materials due to the weak spin-orbit coupling in most transition metal oxides.This work proposes to address these challenges by synthesizing oxide heterostructures of high temperature superconducting cuprates and strongly spin-orbit-coupled iridates. On one hand, the hidden spin rotational symmetry of a two-dimensional iridate layer will be used to create an efficient spin-gate for tuning the antiferromagnetic fluctuation and the superconductivity pairing of the cuprate layer with an external magnetic field. On the other hand, the symmetry configuration of the iridate layer will be tailored to stabilize various topological semimetallic states of the pseudospin-half electrons, which will further experience the superconducting proximity effect from the cuprate layer to search for topological superconducting states at the interfaces. The PI will leverage on atomic layering epitaxial growth to synthesize different prototypes of cuprateiridate interfacial structures and examine the latent charge-spin-orbital reconstructions due to interfacial bonding. The momentum-dependent quasiparticle excitations of the electronic and mangetic degrees of freedom, such as the band structure and magnon dispersion, will be characterized by advanced analytical tools, including in situ photoemission spectroscopy, scanning tunneling microscopy, and ex situ resonant x-ray spectroscopy/scattering. The results are expected to establish understanding of the interplay and merge of correlated and topological electronic statesfor developing functional heterostructures and topological superconductors at high temperatures.The successful outcome of the proposed work will facilitate novel electromagnetic devices and applications with higher energy efficiency and more secured operation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 31, 2020
- Source ID
- N000142012809
Entities
People
- Jian Liu
Organizations
- Office of Naval Research
- United States Navy
- University of Tennessee