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Huai X, Acheampong E, Delles E, Winiarski MJ, Sorolla M, Nassar L, Liang M, Ramette C, Ji H, Scheie A, Calder S, Mourigal M, Tran TT. Noncentrosymmetric Triangular Magnet CaMnTeO 6: Strong Quantum Fluctuations and Role of s 0 versus s 2 Electronic States in Competing Exchange Interactions. Adv Mater 2024:e2313763. [PMID: 38506567 DOI: 10.1002/adma.202313763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 03/12/2024] [Indexed: 03/21/2024]
Abstract
Noncentrosymmetric triangular magnets offer a unique platform for realizing strong quantum fluctuations. However, designing these quantum materials remains an open challenge attributable to a knowledge gap in the tunability of competing exchange interactions at the atomic level. Here, a new noncentrosymmetric triangular S = 3/2 magnet CaMnTeO6 is created based on careful chemical and physical considerations. The model material displays competing magnetic interactions and features nonlinear optical responses with the capability of generating coherent photons. The incommensurate magnetic ground state of CaMnTeO6 with an unusually large spin rotation angle of 127°(1) indicates that the anisotropic interlayer exchange is strong and competing with the isotropic interlayer Heisenberg interaction. The moment of 1.39(1) µB, extracted from low-temperature heat capacity and neutron diffraction measurements, is only 46% of the expected value of the static moment 3 µB. This reduction indicates the presence of strong quantum fluctuations in the half-integer spin S = 3/2 CaMnTeO6 magnet, which is rare. By comparing the spin-polarized band structure, chemical bonding, and physical properties of AMnTeO6 (A = Ca, Sr, Pb), how quantum-chemical interpretation can illuminate insights into the fundamentals of magnetic exchange interactions, providing a powerful tool for modulating spin dynamics with atomically precise control is demonstrated.
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Affiliation(s)
- Xudong Huai
- Department of Chemistry, Clemson University, Clemson, SC, 29634, USA
| | | | - Erich Delles
- Department of Chemistry, Clemson University, Clemson, SC, 29634, USA
| | - Michał J Winiarski
- Applied Physics and Mathematics and Advanced Materials Center, Gdansk University of Technology, Gdansk, 80-233, Poland
| | - Maurice Sorolla
- Institute of Chemistry, University of the Philippines Diliman, Quezon City, 1101, Philippines
| | - Lila Nassar
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Mingli Liang
- Department of Chemistry, University of Houston, Houston, TX, 77204, USA
| | - Caleb Ramette
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Huiwen Ji
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Allen Scheie
- MPA-Q, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Stuart Calder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Martin Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Thao T Tran
- Department of Chemistry, Clemson University, Clemson, SC, 29634, USA
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Gatasheh MK, Daoud MS, Kassim H. Bandgap Narrowing of BaTiO 3-Based Ferroelectric Oxides through Cobalt Doping for Photovoltaic Applications. Materials (Basel) 2023; 16:7528. [PMID: 38138671 PMCID: PMC10745005 DOI: 10.3390/ma16247528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 08/22/2023] [Accepted: 08/28/2023] [Indexed: 12/24/2023]
Abstract
Following the finding of power conversion efficiency above the Shockley-Queisser limit in BaTiO3 (BTO) crystals, ferroelectric oxides have attracted scientific interest in ferroelectric photovoltaics (FPV). However, since ferroelectric oxides have a huge bandgap (>3 eV), progress in this sector is constrained. This paper proposes and demonstrates a new ferroelectric BaTi1-xCoxO3 powder (0 ≤ x ≤ 0.08), abbreviated as BTCx, that exhibited a bandgap decrease with increased Co content. Notably, changing the composition from x = 0.0 to 0.08 caused the system to show a bandgap drop from 3.24 to 2.42 eV. The ideal design with x = 0.08 displayed an abnormal PV response. Raman spectroscopy measurements were used to investigate the cause of the bandgap decrease, and density functional theory was used to interpret the analyzed results. According to our findings, Co2+ doping and oxygen octahedral distortions enhance bandgap reduction. This research sheds light on how bandgap tuning developed and laid the way for investigating novel low-bandgap ferroelectric materials for developing next-generation photovoltaic applications.
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Affiliation(s)
- Mansour K. Gatasheh
- Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; (M.K.G.); (M.S.D.)
| | - Mohamed Saad Daoud
- Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; (M.K.G.); (M.S.D.)
| | - Hamoud Kassim
- Department of Physics & Astronomy, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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Stanton R, Trivedi DJ. Pyrovskite: A software package for the high-throughput construction, analysis, and featurization of two- and three-dimensional perovskite systems. J Chem Phys 2023; 159:064803. [PMID: 37555613 DOI: 10.1063/5.0159407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/24/2023] [Indexed: 08/10/2023] Open
Abstract
The increased computational and experimental interest in perovskite systems comprising novel phases and reduced dimensionality has greatly expanded the search space for this class of materials. In similar fields, unified frameworks exist for the procedural generation and subsequent analysis of these complex condensed matter systems. Given the relatively recent rise in popularity of these novel perovskite phases, such a framework is yet to be created. In this work, we introduce Pyrovskite, an open source software package, to aid in both the high-throughput and fine-grained generation, simulation, and subsequent analysis of this expanded family of perovskite systems. Additionally, we introduce a new descriptor for octahedral distortions in systems, including, but not limited to, perovskites. This descriptor quantifies diagonal displacements of the B-site cation in a BX6 octahedral coordination environment, which has been shown to contribute to increased Rashba-Dresselhaus splitting in perovskite systems.
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Affiliation(s)
- Robert Stanton
- Department of Physics, Clarkson University, Potsdam, New York 13699, USA
| | - Dhara J Trivedi
- Department of Physics, Clarkson University, Potsdam, New York 13699, USA
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