Negative-pressure polymorphs made by heterostructural alloying
| Autor: | Aaron M. Holder, Sebastian Siol, Andriy Zakutayev, Laura T. Schelhas, John D. Perkins, Philip A. Parilla, James Steffes, Kevin H. Stone, Lauren M. Garten, Stephan Lany, William Tumas, Bryan D. Huey, Michael F. Toney |
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| Rok vydání: | 2018 |
| Předmět: |
Multidisciplinary
Materials science Materials Science Alloy SciAdv r-articles 02 engineering and technology Electron engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Piezoelectricity 0104 chemical sciences Effective mass (solid-state physics) Polymorphism (materials science) Chemical physics engineering Natural phenomenon 0210 nano-technology Research Articles Research Article Wurtzite crystal structure |
| Zdroj: | Science Advances |
| ISSN: | 2375-2548 |
| DOI: | 10.1126/sciadv.aaq1442 |
| Popis: | Mixing materials with different crystal structures leads to new phases that otherwise would require negative pressure to be made. The ability of a material to adopt multiple structures, known as polymorphism, is a fascinating natural phenomenon. Various polymorphs with unusual properties are routinely synthesized by compression under positive pressure. However, changing a material’s structure by applying tension under negative pressure is much more difficult. We show how negative-pressure polymorphs can be synthesized by mixing materials with different crystal structures—a general approach that should be applicable to many materials. Theoretical calculations suggest that it costs less energy to mix low-density structures than high-density structures, due to less competition for space between the atoms. Proof-of-concept experiments confirm that mixing two different high-density forms of MnSe and MnTe stabilizes a Mn(Se,Te) alloy with a low-density wurtzite structure. This Mn(Se,Te) negative-pressure polymorph has 2× to 4× lower electron effective mass compared to MnSe and MnTe parent compounds and has a piezoelectric response that none of the parent compounds have. This example shows how heterostructural alloying can lead to negative-pressure polymorphs with useful properties—materials that are otherwise nearly impossible to make. |
| Databáze: | OpenAIRE |
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