Abstract
Electrides are an unusual family of materials that feature loosely bonded electrons that occupy special interstitial sites and serve as anions. They are attracting increasing attention because of their wide range of exotic physical and chemical properties. Despite the critical role of the anionic electrons in inducing these properties, their presence has not been directly observed experimentally. Here, we visualize the columnar anionic electron density within the prototype electride Y5Si3 with sub-angstrom spatial resolution using differential phase-contrast imaging in a scanning transmission electron microscope. The data further reveal an unexpected charge variation at different anionic sites. Density functional theory simulations show that the presence of trace H impurities is the cause of this inhomogeneity. The visualization and quantification of charge inhomogeneities in crystals will serve as valuable input in future theoretical predictions and experimental analysis of exotic properties in electrides and materials beyond.
| Original language | English |
|---|---|
| Article number | eabe6819 |
| Journal | Science Advances |
| Volume | 7 |
| Issue number | 15 |
| DOIs | |
| State | Published - Apr 7 2021 |
Funding
The microscopy work was supported by an Early Career project supported by DOE Office of Science FWP #ERKCZ55-KC040304. All microscopy technique development was performed and supported by Oak Ridge National Laboratory's (ORNL) Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. Q.Z., J.Y., and B.C.S. were supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. Q.Z. thanks the partial support by the NSF-MRSEC. Theoretical work by T.F. and S.T.P. was supported, in part, by DOE grant DE-FG0209ER46554 and by the McMinn Endowment. Y.I., N.S., and R.I. were supported by the Nanotechnology Platform (project no.12024046) from MEXT, Japan, JST-SENTAN, and JST-PRESTO, respectively. The computations partially used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility funded through contract no. DE-AC02-05CH11231, and partially used the Extreme Science and Engineering Discovery Environment (XSEDE). The neutron scattering experiment was performed at ORNL's Spallation Neutron Source, supported by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. DOE, under contract no. DE-AC0500OR22725 with UT Battelle, LLC.
| Funders | Funder number |
|---|---|
| Center for Nanophase Materials Sciences | |
| JST-PRESTO | DE-AC02-05CH11231 |
| JST-SENTAN | |
| MEXT, Japan | |
| McMinn Endowment | 12024046 |
| NSF-MRSEC | DE-FG0209ER46554 |
| Scientific User Facilities Division | |
| U.S. Department of Energy | DE-AC0500OR22725 |
| Office of Science | 55-KC040304 |
| Basic Energy Sciences | |
| Oak Ridge National Laboratory | |
| Division of Materials Sciences and Engineering |