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Islam J, Ahamed M, Alam MS, Bahadur NM. Physical properties of newly synthesized noncentrosymmetric TaIr 2B 2 and NbIr 2B 2 superconductors: an extensive comparison of GGA and LDA functional investigations. RSC Adv 2024; 14:17140-17151. [PMID: 38831771 PMCID: PMC11145744 DOI: 10.1039/d4ra02822h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/13/2024] [Indexed: 06/05/2024] Open
Abstract
In recent years, noncentrosymmetric (NCS) structural compounds have received much attention from the scientific community in the exploration for the unconventional nature of superconductivity with exciting physical properties. This study uses the comprehensive generalized gradient approximation (GGA) and local density approximation (LDA) to gain insights into the physical properties of two recently synthesized Ir-based NCS superconductors, TaIr2B2 and NbIr2B2. The structural parameters, mechanical performance, electronic structure, Debye temperature, melting temperature, electronic specific heat, and electron-phonon coupling constant of TaIr2B2 and NbIr2B2 are explored and discussed in detail. Density functional theory (DFT) optimized structural parameters of both NCS phases agree well with experimental observation. Both GGA and LDA calculations show that the compounds are ductile, machinable, mechanically stable, and anisotropic in nature. The elastic moduli and hardness calculations reveal that TaIr2B2 is harder than NbIr2B2. The calculation of the melting temperature reveals that TaIr2B2 is more suitable for high temperature technology applications compared to NbIr2B2. Both GGA and LDA functionals reveal that the optical functions are very similar. Both compounds display a significant amount of reflectivity spectra over a wide range of photon energies. The GGA functional reveals a somewhat higher density of states value compared to that of LDA. The present calculated values of the electron-phonon coupling constant of both compounds are consistent with values previously reported from experimental studies.
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Affiliation(s)
- Jakiul Islam
- Department of Physics, Noakhali Science and Technology University Noakhali 3814 Bangladesh
| | - Mohasena Ahamed
- Department of Mathematics, Hajee Mohammad Danesh Science and Technology University Dinajpur Bangladesh
| | - Md Saiful Alam
- Department of Applied Chemistry and Chemical Engineering, Noakhali Science and Technology University Noakhali 3814 Bangladesh
| | - Newaz Mohammad Bahadur
- Department of Chemistry, Noakhali Science and Technology University Noakhali 3814 Bangladesh
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Agnarelli L, Prots Y, Krnel M, Svanidze E, König M, Schmidt M, Burkhardt U, Leithe-Jasper A, Grin Y. Charge Transfer in Be-Ru Compounds. Chemistry 2023; 29:e202302301. [PMID: 37740670 DOI: 10.1002/chem.202302301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023]
Abstract
During the investigation of the binary system Be-Ru two new phases - Be7 Ru4 and Be12 Ru7 - with similar compositions (63.6 at. % Be and 63.2 at. % Be, respectively), are discovered. They both represent new structural prototypes. The phases are located between Be2 Ru (Fe2 P-type structure) and Be3 Ru2 (U3 Si2 -type structure) in the phase diagram. This explains why their crystal structures, solved and refined from single crystal X-ray diffraction data, are described as 2D intergrowth of Fe2 P and U3 Si2 motives. The calculated electronic density of stats (DOS) reveals pronounced minima in the vicinity of the Fermi level for both compounds. Position-space analysis of chemical bonding exhibits the formation of three- and four-atomic polar bonds, involving both, Ru and Be, atoms, and a strong charge transfer from Be to the more electronegative Ru.
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Affiliation(s)
- Laura Agnarelli
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Yurii Prots
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Mitja Krnel
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Eteri Svanidze
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Markus König
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Marcus Schmidt
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Ulrich Burkhardt
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Andreas Leithe-Jasper
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Yuri Grin
- Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
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Shang T, Svanidze E, Shiroka T. Probing the superconducting pairing of the La 4Be 33Pt 16alloy via muon-spin spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:105601. [PMID: 37988753 DOI: 10.1088/1361-648x/ad0e93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 11/21/2023] [Indexed: 11/23/2023]
Abstract
We report a study of the superconducting pairing of the noncentrosymmetric La4Be33Pt16alloy using muon-spin rotation and relaxation (µSR) technique. BelowTc=2.4 K, La4Be33Pt16exhibits bulk superconductivity (SC), here characterized by heat-capacity and magnetic-susceptibility measurements. The temperature dependence of the superfluid densityρsc(T), extracted from the transverse-fieldµSR measurements, reveals a nodeless SC in La4Be33Pt16. The best fit ofρsc(T)using ans-wave model yields a magnetic penetration depthλ0=542 nm and a superconducting gapΔ0=0.37 meV at zero Kelvin. The single-gapped superconducting state is further evidenced by the temperature-dependent electronic specific heatCe(T)/Tand the linear field-dependent electronic specific-heat coefficientγH(H). The zero-fieldµSR spectra collected in the normal- and superconducting states of La4Be33Pt16are almost identical, confirming the absence of an additional field-related relaxation and, thus, of spontaneous magnetic fields belowTc. The nodeless SC combined with a preserved time-reversal symmetry in the superconducting state proves that the spin-singlet pairing is dominant in La4Be33Pt16. This material represents yet another example of a complex system showing only a conventional behavior, in spite of a noncentrosymmetric structure and a sizeable spin-orbit coupling.
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Affiliation(s)
- Tian Shang
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, People's Republic of China
| | - Eteri Svanidze
- Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
| | - Toni Shiroka
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Laboratorium für Festkörperphysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
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Asrafusjaman M, Islam J, Rahman MA, Hossain AKMA. Investigation of the Influence of Pressure on the Physical Properties and Superconducting Transition Temperature of Chiral Noncentrosymmetric TaRh 2B 2 and NbRh 2B 2. ACS OMEGA 2023; 8:21813-21822. [PMID: 37360420 PMCID: PMC10286279 DOI: 10.1021/acsomega.3c01461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/09/2023] [Indexed: 06/28/2023]
Abstract
TaRh2B2 and NbRh2B2 compounds exhibit noncentrosymmetric superconductivity with a chiral structure. Density functional theory-based ab-initio calculations have been executed to analyze the structural properties, mechanical stability, ductility/brittleness behaviors, Debye temperature, melting temperature, optical response to incident photon energy, electronic characteristics, and superconducting transition temperature of chiral TaRh2B2 and NbRh2B2 compounds under pressure up to 16 GPa. Both the chiral phases are mechanically stable and exhibit ductile nature under the studied pressure. The maximum value of the Pugh ratio (an indicator of ductile/brittle behaviors) is observed to be 2.55 (for NbRh2B2) and 2.52 (for TaRh2B2) at 16 GPa. The lowest value of the Pugh ratio is noticed at 0 GPa for both these chiral compounds. The analysis of reflectivity spectra suggests that both the chiral compounds can be used as efficient reflecting materials in the visible energy region. At 0 GPa, the calculated densities of states (DOSs) at the Fermi level are found to be 1.59 and 2.13 states eV-1 per formula unit for TaRh2B2 and NbRh2B2, respectively. The DOS values of both the chiral phases do not alter significantly with applied pressure. The shape of the DOS curve of both compounds remains almost invariant with applied pressure. The pressure-induced variation of Debye temperatures of both compounds is observed, which may cause the alternation of the superconducting transition temperature, Tc, with applied pressure. The probable changing of Tc with pressure has been analyzed from the McMillan equation.
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