Abstract
The temperature dependence of the local structure of PbSe has been investigated using pair distribution function (PDF) analysis of x-ray and neutron powder diffraction data and density functional theory (DFT) calculations. Observation of non-Gaussian PDF peaks at high temperature indicates the presence of significant anharmonicity, which can be modeled as Pb off-centering along [100] directions that grows on warming similar to the behavior seen in PbTe and PbS and sometimes called emphanisis. Interestingly, the emphanitic response is smaller in PbSe than in both PbS and PbTe indicating a nonmonotonic response with chalcogen atomic number in the PbQ (Q = S, Se, Te) series. The DFT calculations indicate a correlation between band gap and the amplitude of [100] dipolar distortion, suggesting that emphanisis may be behind the anomalous composition and temperature dependencies of the band gaps in this series.
| Original language | English (US) |
|---|---|
| Article number | 144108 |
| Journal | Physical Review B |
| Volume | 98 |
| Issue number | 14 |
| DOIs | |
| State | Published - Oct 12 2018 |
Funding
oratory, was supported by DOE-BES under Contract No. DESC0012704. B.S. and N.A.S. acknowledge support from ETH Z\u00FCrich, the ERC Advanced Grant program (No. 291151), and the Swiss National Supercomputing Centre (CSCS) under Project ID s624. Work at Brookhaven National Laboratory was supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (DOE-BES) under Contract DESC0012704. Work at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering. The neutron diffraction measurements were carried out at NPDF instrument of the Work at Brookhaven National Laboratory was supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (DOE-BES) under Contract DE-SC0012704. Work at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering. The neutron diffraction measurements were carried out at NPDF instrument of the Lujan Neutron Scattering Center at Los Alamos National Laboratory, and the x-ray experiments were carried out at beamline 28-ID-2 (XPD) of the National Synchrotron Light Source II at Brookhaven National Laboratory. Use of the National Synchrotron Light Source II, Brookhaven National Laboratory, was supported by DOE-BES under Contract No. DE-SC0012704. B.S. and N.A.S. acknowledge support from ETH Z\u00FCrich, the ERC Advanced Grant program (No. 291151), and the Swiss National Supercomputing Centre (CSCS) under Project ID s624.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics