Abstract
We have applied the diffusion quantum Monte Carlo (DMC) method to study the electron confinement and magnetic structure in the (LaTiO3)1/(SrTiO3)5 heterostructure. The DMC results were compared with various density functional theory (DFT) methods, including local density approximation (LDA), generalized gradient approximation (GGA), LDA+U, and GGA+U, as well as the recently proposed strongly constrained appropriately normed (SCAN) and van der Waals-Bayesian error estimation functional (vdW-BEEF). We found that many-body correlations are crucial to accurately describe the localization of the two-dimensional (2D) electron gas around the lanthanum planes. DMC predicts 20% more electron density within the first interfacial titanium layer in (LaTiO3)1/(SrTiO3)5 than LDA+U, suggesting that the degree of confinement of the 2D electron gas in the interfacial region is underestimated with semilocal DFT approximations. DMC yields the ferromagnetic (FM) state as the ground state of (LaTiO3)1/(SrTiO3)5 and the antiferromagnetic (AFM) and nonmagnetic (NM) states that are higher in energy by 37(15) and 238(15) meV per lanthanum atom at the interface, respectively. Most DFT methods yield the FM and NM states within less than 25 meV in energy and could not find the AFM state.
| Original language | English |
|---|---|
| Pages (from-to) | 643-650 |
| Number of pages | 8 |
| Journal | Journal of Chemical Theory and Computation |
| Volume | 16 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 14 2020 |
Funding
This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). The work was supported by the Materials Sciences and Engineering Division of the Office of Basic Energy Sciences (BES-MSED) US Department of Energy (DOE).*%blankline%* The work was supported by the Materials Sciences and Engineering Division of the Office of Basic Energy Sciences (BES-MSED), US Department of Energy (DOE). J.A.S. was supported in part by the 2018–2019 Start-Up funds of the University of Puerto Rico at Cayey and BES-MSED through summer research visits to the Oak Ridge National Laboratory (ORNL). Computational resources were provided by the Oak Ridge Leadership Computing Facility at ORNL, supported by the DOE Office of Science under contract DE-AC05-00OR22725, and the High-Performance Computing Facility at the University of Puerto Rico, which is supported by an Institutional Development Award (IDeA) INBRE Grant Number P20GM103475 from the National Institute of General Medical Sciences (NIGMS), a component of the National Institutes of Health (NIH), and the Bioinformatics Research Core of the INBRE. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of NIGMS or NIH.
| Funders | Funder number |
|---|---|
| BES-MSED | |
| DOE Office of Science | |
| High-Performance Computing Facility | P20GM103475 |
| Oak Ridge National Laboratory | |
| Office of Basic Energy Sciences | |
| US Department of Energy | |
| UT-Battelle | DE-AC05-00OR22725 |
| National Institutes of Health | |
| U.S. Department of Energy | |
| National Institute of General Medical Sciences | |
| Puerto Rico Sea Grant, University of Puerto Rico | |
| Basic Energy Sciences | |
| Oak Ridge National Laboratory | ORNL |
| Center for Outcomes Research and Evaluation, Yale School of Medicine | |
| Division of Materials Sciences and Engineering |