New Zirconium Diboride Polymorphs—First-Principles Calculations
Two new hypothetical zirconium diboride (ZrB<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>2</mn> </msub> </semantics> </math> </inline-formula>) polymorphs: (<i>hP6</i>-P6<...
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MDPI AG
2020-07-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/13/13/3022 |
| _version_ | 1797563191700488192 |
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| author | Marcin Maździarz Tomasz Mościcki |
| author_facet | Marcin Maździarz Tomasz Mościcki |
| author_sort | Marcin Maździarz |
| collection | DOAJ |
| description | Two new hypothetical zirconium diboride (ZrB<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>2</mn> </msub> </semantics> </math> </inline-formula>) polymorphs: (<i>hP6</i>-P6<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>3</mn> </msub> </semantics> </math> </inline-formula>/mmc-space group, no. 194) and (<i>oP6</i>-Pmmn-space group, no. 59), were thoroughly studied under the first-principles density functional theory calculations from the structural, mechanical and thermodynamic properties point of view. The proposed phases are thermodynamically stable (negative formation enthalpy). Studies of mechanical properties indicate that new polymorphs are less hard than the known phase (<i>hP3</i>-P6/mmm-space group, no. 191) and are not brittle. Analysis of phonon band structure and density of states (DOS) also show that the phonon modes have positive frequencies everywhere and the new ZrB<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>2</mn> </msub> </semantics> </math> </inline-formula> phases are not only mechanically but also dynamically stable. The estimated acoustic Debye temperature, <inline-formula> <math display="inline"> <semantics> <msub> <mi>Θ</mi> <mi>D</mi> </msub> </semantics> </math> </inline-formula>, for the two new proposed ZrB<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>2</mn> </msub> </semantics> </math> </inline-formula> phases is about 760 K. The thermodynamic properties such as internal energy, free energy, entropy and constant-volume specific heat are also presented. |
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| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T18:40:06Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-f2427cfc788e4632b2d2f7ebc5629cd12023-11-20T05:59:30ZengMDPI AGMaterials1996-19442020-07-011313302210.3390/ma13133022New Zirconium Diboride Polymorphs—First-Principles CalculationsMarcin Maździarz0Tomasz Mościcki1Institute of Fundamental Technological Research Polish Academy of Sciences, 02-106 Warsaw, PolandInstitute of Fundamental Technological Research Polish Academy of Sciences, 02-106 Warsaw, PolandTwo new hypothetical zirconium diboride (ZrB<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>2</mn> </msub> </semantics> </math> </inline-formula>) polymorphs: (<i>hP6</i>-P6<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>3</mn> </msub> </semantics> </math> </inline-formula>/mmc-space group, no. 194) and (<i>oP6</i>-Pmmn-space group, no. 59), were thoroughly studied under the first-principles density functional theory calculations from the structural, mechanical and thermodynamic properties point of view. The proposed phases are thermodynamically stable (negative formation enthalpy). Studies of mechanical properties indicate that new polymorphs are less hard than the known phase (<i>hP3</i>-P6/mmm-space group, no. 191) and are not brittle. Analysis of phonon band structure and density of states (DOS) also show that the phonon modes have positive frequencies everywhere and the new ZrB<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>2</mn> </msub> </semantics> </math> </inline-formula> phases are not only mechanically but also dynamically stable. The estimated acoustic Debye temperature, <inline-formula> <math display="inline"> <semantics> <msub> <mi>Θ</mi> <mi>D</mi> </msub> </semantics> </math> </inline-formula>, for the two new proposed ZrB<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mn>2</mn> </msub> </semantics> </math> </inline-formula> phases is about 760 K. The thermodynamic properties such as internal energy, free energy, entropy and constant-volume specific heat are also presented.https://www.mdpi.com/1996-1944/13/13/3022zirconium diborideab initio calculationsmechanical propertieselastic propertiesphonons |
| spellingShingle | Marcin Maździarz Tomasz Mościcki New Zirconium Diboride Polymorphs—First-Principles Calculations Materials zirconium diboride ab initio calculations mechanical properties elastic properties phonons |
| title | New Zirconium Diboride Polymorphs—First-Principles Calculations |
| title_full | New Zirconium Diboride Polymorphs—First-Principles Calculations |
| title_fullStr | New Zirconium Diboride Polymorphs—First-Principles Calculations |
| title_full_unstemmed | New Zirconium Diboride Polymorphs—First-Principles Calculations |
| title_short | New Zirconium Diboride Polymorphs—First-Principles Calculations |
| title_sort | new zirconium diboride polymorphs first principles calculations |
| topic | zirconium diboride ab initio calculations mechanical properties elastic properties phonons |
| url | https://www.mdpi.com/1996-1944/13/13/3022 |
| work_keys_str_mv | AT marcinmazdziarz newzirconiumdiboridepolymorphsfirstprinciplescalculations AT tomaszmoscicki newzirconiumdiboridepolymorphsfirstprinciplescalculations |