Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles Studies
In this manuscript, we report the density functional theory-based first principles study of the structural and vibrational properties of technologically relevant M′ fergusonite (<i>P</i>2/<i>c</i>)-structured NdTaO<sub>4</sub> and SmTaO<sub>4</sub> und...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-02-01
|
| Series: | Crystals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4352/13/2/254 |
| _version_ | 1797621596932800512 |
|---|---|
| author | Saheli Banerjee Amit Tyagi Alka B. Garg |
| author_facet | Saheli Banerjee Amit Tyagi Alka B. Garg |
| author_sort | Saheli Banerjee |
| collection | DOAJ |
| description | In this manuscript, we report the density functional theory-based first principles study of the structural and vibrational properties of technologically relevant M′ fergusonite (<i>P</i>2/<i>c</i>)-structured NdTaO<sub>4</sub> and SmTaO<sub>4</sub> under compression. For NdTaO<sub>4</sub> and SmTaO<sub>4,</sub> ambient unit cell parameters, along with constituent polyhedral volume and bond lengths, have been compared with earlier reported parameters for EuTaO<sub>4</sub> and GdTaO<sub>4</sub> for a better understanding of the role of lanthanide radii on the primitive unit cell. For both the compounds, our calculations show the presence of first-order monoclinic to tetragonal phase transition accompanied by nearly a 1.3% volume collapse and an increase in oxygen coordination around the tantalum (Ta) cation from ambient six to eight at phase transition. A lower bulk modulus obtained in the high-pressure tetragonal phase when compared to the ambient monoclinic phase is indicative of the more compressible unit cell under pressure. Phonon modes are calculated for the ambient and high-pressure phases with compression for both the compounds along with their pressure coefficients. One particular IR mode has been observed to show red shift in the ambient monoclinic phase, possibly leading to the instability in the compounds under compression. |
| first_indexed | 2024-03-11T08:58:14Z |
| format | Article |
| id | doaj.art-c4375589de304cd08cad278e49b9f405 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-11T08:58:14Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Crystals |
| spelling | doaj.art-c4375589de304cd08cad278e49b9f4052023-11-16T19:55:38ZengMDPI AGCrystals2073-43522023-02-0113225410.3390/cryst13020254Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles StudiesSaheli Banerjee0Amit Tyagi1Alka B. Garg2High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, IndiaHigh Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, IndiaHigh Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, IndiaIn this manuscript, we report the density functional theory-based first principles study of the structural and vibrational properties of technologically relevant M′ fergusonite (<i>P</i>2/<i>c</i>)-structured NdTaO<sub>4</sub> and SmTaO<sub>4</sub> under compression. For NdTaO<sub>4</sub> and SmTaO<sub>4,</sub> ambient unit cell parameters, along with constituent polyhedral volume and bond lengths, have been compared with earlier reported parameters for EuTaO<sub>4</sub> and GdTaO<sub>4</sub> for a better understanding of the role of lanthanide radii on the primitive unit cell. For both the compounds, our calculations show the presence of first-order monoclinic to tetragonal phase transition accompanied by nearly a 1.3% volume collapse and an increase in oxygen coordination around the tantalum (Ta) cation from ambient six to eight at phase transition. A lower bulk modulus obtained in the high-pressure tetragonal phase when compared to the ambient monoclinic phase is indicative of the more compressible unit cell under pressure. Phonon modes are calculated for the ambient and high-pressure phases with compression for both the compounds along with their pressure coefficients. One particular IR mode has been observed to show red shift in the ambient monoclinic phase, possibly leading to the instability in the compounds under compression.https://www.mdpi.com/2073-4352/13/2/254high pressurerare earth tantalatesfirst principles calculationsRaman modesphase transition |
| spellingShingle | Saheli Banerjee Amit Tyagi Alka B. Garg Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles Studies Crystals high pressure rare earth tantalates first principles calculations Raman modes phase transition |
| title | Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles Studies |
| title_full | Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles Studies |
| title_fullStr | Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles Studies |
| title_full_unstemmed | Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles Studies |
| title_short | Pressure-Induced Monoclinic to Tetragonal Phase Transition in <i>R</i>TaO<sub>4</sub> (<i>R</i> = Nd, Sm): DFT-Based First Principles Studies |
| title_sort | pressure induced monoclinic to tetragonal phase transition in i r i tao sub 4 sub i r i nd sm dft based first principles studies |
| topic | high pressure rare earth tantalates first principles calculations Raman modes phase transition |
| url | https://www.mdpi.com/2073-4352/13/2/254 |
| work_keys_str_mv | AT sahelibanerjee pressureinducedmonoclinictotetragonalphasetransitioniniritaosub4subirindsmdftbasedfirstprinciplesstudies AT amittyagi pressureinducedmonoclinictotetragonalphasetransitioniniritaosub4subirindsmdftbasedfirstprinciplesstudies AT alkabgarg pressureinducedmonoclinictotetragonalphasetransitioniniritaosub4subirindsmdftbasedfirstprinciplesstudies |