First-Principles Computational Studies of Novel Correlated-Electron Materials
Abstract
Strain-Coupled Properties of Trans Metal OxidesCorrelated-electron materials are of great interest for emerging technological applications. The rich interplay among charge, lattice, orbital, and spin degrees offreedom and with external fields, strain, and temperature offers many possibilities for novel device applications. Recent novel nanoscale synthesis methods of low-dimensional systems such as epitaxial ultra-thin films and one-dimensional wires are especially of interest, since, by contrast with three-dimensional bulk materials, it is possible to tune their key properties (such as conductivity) using external fields and anisotropic strain. We will investigate the properties of transition metal oxides and heterostructures being considered to replace standard materials in device applications such as field-effect transistors. We will study the functionalization, with correlated-electron atoms, of recently fabricated one-atom wide carbon chains (carbyne) of unprecedented micrometer length-scale. These long-sought sp bonded C-C chains are the one-dimensionalcounterparts of graphene. Other one-dimensional systems will also be investigated for use in nanoelectronic and spintronic applications. We will carry out density functional theory (DFT) and quantum Monte Carlo (QMC) calculations to predict and elucidate theproperties of these materials. DFT is an extremely successful approach and is the workhorse method for most materials calculations. DFT, however, is a mean-field method, depending on an approximate exchange-correlation functional. This is an uncontrolled approximation, which can fail for materials with strongly correlated electrons. Where highly accurate results are required, we will use auxiliary-field QMC (AFQMC) calculations. AFQMC is a near-exact full many-body and is the most accurate method for extended systems. We will further develop our downfolding approach formore efficient AFQMC calculations. Our goal is to use the full spectrum of state-of-theart first-principles methods, from DFT to AFQMC, to better understand and design new low-dimensional materials for novel device applications.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2017
- Source ID
- N000141712237
Entities
People
- Henry Krakauer
Organizations
- College of William & Mary
- Office of Naval Research
- United States Navy