PhD Projects 2015 Surfaces, Interfaces & Thin Films Group Growth and characterisation of perovskite based complex oxides Surfaces, Interfaces & Thin Films Group / Ferroelectric Materials Group Joint PhD Project This project will involve the growth and characterization of thin films of perovskite based oxide materials (ABO3). These thin films will be grown using pulsed laser deposition (PLD) to ensure control of the stoichiometry of the material, which is monitored in-­‐situ using reflection high energy electron diffraction (RHEED). This allows atomic scale engineering of the microstructure, including establishing the conditions for layer-­‐by-­‐layer growth for the construction of artificial materials e.g. superlattice structures of alternating oxide materials. These types of structures typically have coupled properties between the layers e.g. ferroelectric or magnetoelectric, or Ruddlesden-­‐Popper type materials, which are layered perovskite-­‐based oxides of the general form An+1BnO3n+1. One such materials system of interest is strontium iridate (Srn+1IrnO3n+1), which under certain variations can be an anti-­‐ferromagnet with a very large spin-­‐orbit splitting, an insulator or metallic [1]. Alternatively if the materials is doped and some of the Ir is replaced, and it could potentially be a new superconductor a low temperatures. The large spin-­‐orbit splitting is particularly interesting as materials which display this property often act as topological insulators. Another such materials system is barium bismate (BaBiO3), another potential superconductor, but which has also recently been identified as a large energy band-­‐gap topological insulator [2]. The aim of this project will be to grow and characterize the surface and bulk materials properties of related complex oxide materials grown using PLD. Ex-­‐situ characterization will include structural, electrical and conductivity measurements, while in-­‐vacuum transfer to a range of surface science chambers with techniques such as X-­‐ray photoelectron spectroscopy (XPS), scanning tunelling microscopy and spectroscopy (STM & STS) and ex-­‐
situ scanning probe microscopy such atomic, conducting, electrostatic, and piezoelectric force microscopy (AFM, CFM, EFM & PFM) at Warwick. In addition, the detailed electronic structure and Fermi surface mapping will be undertaken using high-­‐resolution angle-­‐
resolved photoelectron spectroscopy (ARPES) using synchrotron radiation [3, 4] at the Diamond Light Source in Oxfordshire. References: [1] Y. Okada et al. Nature Materials, 12 (2013) 707. [2] B. Yan, M. Jansen and C. Felser, Nature Physics, 9 (2013) 709 DOI: 10.1038/nphys2762 [3] P.D.C. King et al. Nature Nanotechnology, 9 (2014) 443. DOI: 10.1038/nnano.2014.59 [4] P.D.C. King et al. Nature Communications, 5 (2014) 3414. DOI: 10.1038/ncomms4414 To discuss this project further contact: Professor Chris McConville (c.f.mcconville@warwick.ac.uk) or Professor Marin Alexe (m.alexe@warwick.ac.uk)