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Ho DQ, Hu R, To DQ, Bryant GW, Janotti A. Emerging Nontrivial Topology in Ultrathin Films of Rare-Earth Pnictides. ACS NANO 2023; 17:20991-20998. [PMID: 37870504 DOI: 10.1021/acsnano.3c03307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Thin films of rare-earth monopnictide (RE-V) semimetals are expected to turn into semiconductors due to quantum confinement effects (QCE), lifting the overlap between electron pockets at Brillouin zone edges (X) and hole pockets at the zone center (Γ). Instead, using LaSb as an example, we find the emergence of the quantum spin Hall (QSH) insulator phase in (001)-oriented films as the thickness is reduced to 7, 5, or 3 monolayers (MLs). This is attributed to a strong QCE on the in-plane electron pockets and the lack of quantum confinement on the out-of-plane pocket projected onto the zone center, resulting in a band inversion. Spin-orbit coupling (SOC) opens a sizable nontrivial gap in the band structure of ultrathin films. Such effect is anticipated to be general in rare-earth monopnictides and may lead to interesting phenomena when coupled with the 4f magnetic moments present in other members of this family of materials.
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Affiliation(s)
- Dai Q Ho
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
- Faculty of Natural Sciences, Quy Nhon University, Quy Nhon 590000, Vietnam
| | - Ruiqi Hu
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - D Quang To
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Garnett W Bryant
- Nanoscale Device Characterization Division, Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8423, United States
- University of Maryland, College Park, Maryland 20742, United States
| | - Anderson Janotti
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
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2
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Caroff CM, Girolami GS. Synthesis, Structure, and Properties of Volatile Lanthanide Dialkyltriazenides. Inorg Chem 2022; 61:16740-16749. [PMID: 36206485 DOI: 10.1021/acs.inorgchem.2c02545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several dialkyltriazenide complexes of the lanthanide elements neodymium, europium, and erbium have been prepared; these include the homoleptic complex Er(ButN3But)3, the tetrahydrofuran monoadducts Ln(ButN3But)3(THF) where Ln = Nd or Eu, and the lithium salts [Li(THF)][Ln(MeN3But)4] where Ln = Eu or Er. Crystal structures, nuclear magnetic resonance data, and infrared data are reported for all complexes. The di-tert-butyltriazenide complexes are thermally stable, sublime at reasonably low temperatures, and show smooth volatilization without decomposition, which make them potentially useful in lanthanide separation processes and as chemical vapor deposition precursors for lanthanide nitrides and other phases.
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Affiliation(s)
- Christopher M Caroff
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Gregory S Girolami
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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3
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Uchida M, Sato S, Ishizuka H, Kurihara R, Nakajima T, Nakazawa Y, Ohno M, Kriener M, Miyake A, Ohishi K, Morikawa T, Bahramy MS, Arima TH, Tokunaga M, Nagaosa N, Kawasaki M. Above-ordering-temperature large anomalous Hall effect in a triangular-lattice magnetic semiconductor. SCIENCE ADVANCES 2021; 7:eabl5381. [PMID: 34936456 PMCID: PMC8694614 DOI: 10.1126/sciadv.abl5381] [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: 07/20/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
While anomalous Hall effect (AHE) has been extensively studied in the past, efforts for realizing large Hall response have been mainly limited within intrinsic mechanism. Lately, however, a theory of extrinsic mechanism has predicted that magnetic scattering by spin cluster can induce large AHE even above magnetic ordering temperature, particularly in magnetic semiconductors with low carrier density, strong exchange coupling, and finite spin chirality. Here, we find out a new magnetic semiconductor EuAs, where Eu2+ ions with large magnetic moments form distorted triangular lattice. In addition to colossal magnetoresistance, EuAs exhibits large AHE with an anomalous Hall angle of 0.13 at temperatures far above antiferromagnetic ordering. As also demonstrated by model calculations, observed AHE can be explained by the spin cluster scattering in a hopping regime. Our findings shed light on magnetic semiconductors hosting topological spin textures, developing a field targeting diluted carriers strongly coupled to noncoplanar spin structures.
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Affiliation(s)
- Masaki Uchida
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8550, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
- PRESTO, Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0075, Japan
| | - Shin Sato
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
| | - Hiroaki Ishizuka
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Ryosuke Kurihara
- Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Taro Nakajima
- Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Yusuke Nakazawa
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
| | - Mizuki Ohno
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8550, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
| | - Markus Kriener
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Atsushi Miyake
- Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Kazuki Ohishi
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai 319-1106, Japan
| | - Toshiaki Morikawa
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai 319-1106, Japan
| | - Mohammad Saeed Bahramy
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
| | - Taka-hisa Arima
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Masashi Tokunaga
- Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Naoto Nagaosa
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Masashi Kawasaki
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
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4
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Study of structural, optoelectronic and magnetic properties of Half-Heusler compounds QEuPa (Q= Ba, be, Mg, Sr) using first-principles method. J SOLID STATE CHEM 2021. [DOI: 10.1016/j.jssc.2021.122612] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Zvereva E, Vasilchikova T, Evstigneeva M, Tyureva A, Nalbandyan V, Gonçalves J, Barone P, Stroppa A, Vasiliev A. Chirality and Magnetocaloricity in GdFeTeO 6 as Compared to GdGaTeO 6. MATERIALS 2021; 14:ma14205954. [PMID: 34683545 PMCID: PMC8539160 DOI: 10.3390/ma14205954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 11/16/2022]
Abstract
GdFeTeO6 and GdGaTeO6 have been prepared and their structures refined by the Rietveld method. Both are superstructures of the rosiaite type (space group P3¯1c). Their thermodynamic properties have been investigated by means of magnetization M and specific heat Cp measurements, evidencing the formation of the long-range antiferromagnetic order at TN = 2.4 K in the former compound and paramagnetic behavior down to 2 K in the latter compound. Large magnetocaloric effect allows considering GdFeTeO6 for the magnetic refrigeration at liquid hydrogen stage. Density functional theory calculations produce estimations of leading Gd–Gd, Gd–Fe and Fe–Fe interactions suggesting unique chiral 120° magnetic structure of Fe3+ (S = 5/2) moments and Gd3+ (J = 7/2) moments rotating in opposite directions (clockwise/anticlockwise) within weakly coupled layers of the rosiaite type crystal structure.
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Affiliation(s)
- Elena Zvereva
- Department of Low Temperature Physics and Superconductivity, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.Z.); (T.V.)
| | - Tatyana Vasilchikova
- Department of Low Temperature Physics and Superconductivity, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.Z.); (T.V.)
| | - Maria Evstigneeva
- Department of Chemistry, Southern Federal University, 344090 Rostov-on-Don, Russia; (M.E.); (A.T.); (V.N.)
| | - Angelica Tyureva
- Department of Chemistry, Southern Federal University, 344090 Rostov-on-Don, Russia; (M.E.); (A.T.); (V.N.)
| | - Vladimir Nalbandyan
- Department of Chemistry, Southern Federal University, 344090 Rostov-on-Don, Russia; (M.E.); (A.T.); (V.N.)
| | - João Gonçalves
- Department of Physics and CICECO, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Paolo Barone
- Consiglio Nazionale delle Ricerche, Institute for Superconducting and Innovative Materials and Devices (CNR-SPIN), Area della Ricerca di Tor Vergata, Via del Fosso del Cavaliere 100, I-00133 Rome, Italy;
| | - Alessandro Stroppa
- Consiglio Nazionale delle Ricerche, Institute for Superconducting and Innovative Materials and Devices (CNR-SPIN), c/o Department of Physical and Chemical Sciences, University of L’Aquila, Via Vetoio Coppito, I-67100 L’Aquila, Italy;
| | - Alexander Vasiliev
- Department of Low Temperature Physics and Superconductivity, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.Z.); (T.V.)
- Quantum Functional Materials Laboratory, National University of Science and Technology “MISiS”, 119049 Moscow, Russia
- Correspondence:
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6
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Lone IUN, Sirajuddeen MMS, Khalid S, Raza HH. First-Principles Study on Electronic, Magnetic, Optical, Mechanical, and Thermodynamic Properties of Semiconducting Gadolinium Phosphide in GGA, GGA+U, mBJ, GGA+SOC and GGA+SOC+U approaches. JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM 2021; 34:1523-1538. [PMID: 33841054 PMCID: PMC8019481 DOI: 10.1007/s10948-021-05877-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/27/2021] [Indexed: 06/12/2023]
Abstract
In the current article, the electronic, magnetic, and optical properties of GdP in the hypothetical zinc blende structure have been discussed by using GGA, GGA+U, mBJ, GGA+SOC, and GGA+SOC+U approaches. The energy vs volume plots in the three magnetic states suggest the ferromagnetic phase to be the stable phase of GdP. The cohesive energy calculated for GdP is negative, suggesting the stability of the compound. The electronic band structure calculations predict the binary GdP to be a direct bandgap conventional semiconductor. The optical properties confirm the semiconducting properties of GdP, and the bandgap formation follows Penn's criteria. The elastic constants also confirm the stability of the compound with ductile nature. The thermodynamic properties including Debye temperature, entropy, and specific heat capacity are studied under varying hydrostatic pressures taking into account the quasi-harmonic Debye model. The doping of Cu in the supercell of GdP results in the compound to exhibit half-metallic ferromagnetic properties. The magnetic moments calculated for CuxGd1-xP (x = 0.25) are integer-valued backing its half-metallic character and fit excellent with the Slauter-Pauling rule Zt-8. GdP in the zinc blende structure can prove a potential candidate for optoelectronic devices having better reflectivity in the UV region whereas its doped compounds have the potential to exhibit half-metallic properties useful in spintronics.
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Affiliation(s)
- Ikram Un Nabi Lone
- Department of Physics, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, India
| | | | - Saubia Khalid
- Department of Physics, Women University of A. J&K Bagh, Bagh, 12500 Pakistan
| | - Hafiz Hamid Raza
- Center for Advanced Studies in Physics (CASP), GC University, Lahore, 54000 Pakistan
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7
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Gulebaglan SE, Dogan EK. Investigation of Structural, Electronic, and Dynamic Properties of Half‐Heusler Alloys XCuB (X = Ti, Zr) by First Principles Calculations. CRYSTAL RESEARCH AND TECHNOLOGY 2020. [DOI: 10.1002/crat.202000116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sinem Erden Gulebaglan
- Department of Electric and Energy, Van Vocational School Van Yuzuncu Yil University Van 65080 Turkey
| | - Emel Kilit Dogan
- Van Yuzuncu Yil University Department of Physics Van 65080 Turkey
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8
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Xu J, Wu F, Bao JK, Han F, Xiao ZL, Martin I, Lyu YY, Wang YL, Chung DY, Li M, Zhang W, Pearson JE, Jiang JS, Kanatzidis MG, Kwok WK. Orbital-flop Induced Magnetoresistance Anisotropy in Rare Earth Monopnictide CeSb. Nat Commun 2019; 10:2875. [PMID: 31253766 PMCID: PMC6599061 DOI: 10.1038/s41467-019-10624-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/22/2019] [Indexed: 11/22/2022] Open
Abstract
The charge and spin of the electrons in solids have been extensively exploited in electronic devices and in the development of spintronics. Another attribute of electrons—their orbital nature—is attracting growing interest for understanding exotic phenomena and in creating the next-generation of quantum devices such as orbital qubits. Here, we report on orbital-flop induced magnetoresistance anisotropy in CeSb. In the low temperature high magnetic-field driven ferromagnetic state, a series of additional minima appear in the angle-dependent magnetoresistance. These minima arise from the anisotropic magnetization originating from orbital-flops and from the enhanced electron scattering from magnetic multidomains formed around the first-order orbital-flop transition. The measured magnetization anisotropy can be accounted for with a phenomenological model involving orbital-flops and a spin-valve-like structure is used to demonstrate the viable utilization of orbital-flop phenomenon. Our results showcase a contribution of orbital behavior in the emergence of intriguing phenomena. The orbital degree of freedom can be as important as the charge and spin of the electron to the electronic phenomena. Here the authors show additional minimum in the angle-dependent magnetoresistance (MR) for the low temperature high magnetic field driven ferromagnetic state in CeSb which indicates the orbital flop induced MR anisotropy.
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Affiliation(s)
- Jing Xu
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.,Department of Physics, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Fengcheng Wu
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.,Condensed Matter Theory Center and Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD, 20742, USA
| | - Jin-Ke Bao
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Fei Han
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Zhi-Li Xiao
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA. .,Department of Physics, Northern Illinois University, DeKalb, IL, 60115, USA.
| | - Ivar Martin
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.
| | - Yang-Yang Lyu
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.,Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, China
| | - Yong-Lei Wang
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.,Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, China
| | - Duck Young Chung
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Mingda Li
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Wei Zhang
- Department of Physics, Oakland University, Rochester, MI, 48309, USA.
| | - John E Pearson
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Jidong S Jiang
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Mercouri G Kanatzidis
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.,Department of Chemistry, Northwestern University, Evanston, IL, 60208, USA
| | - Wai-Kwong Kwok
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
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9
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Static and Dynamical Properties of heavy actinide Monopnictides of Lutetium. Sci Rep 2016; 6:29309. [PMID: 27384709 PMCID: PMC4935863 DOI: 10.1038/srep29309] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/03/2016] [Indexed: 11/08/2022] Open
Abstract
In this work, density functional theory within the framework of generalized gradient approximation has been used to investigate the structural, elastic, mechanical, and phonon properties of lutetium monopnictides in rock-salt crystal structure. The spin orbit coupling and Hubbard-U corrections are included to correctly predict the essential properties of these compounds. The elastic constants, Young's modulus E, Poisson's ratio v, shear modulus G, anisotropy factor A and Pugh's ratio are computed. We found that all lutetium monopnictides are anisotropic and show brittle character. From the wave velocities along [100], [110] and [111] directions, melting temperature of lutetium monopnictides are predicted. Dynamical stability of these monopnictides has been studied by density functional perturbation theory.
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10
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Gupta DC, Bhat IH. Electronic, ductile, phase transition and mechanical properties of Lu-monopnictides under high pressures. J Mol Model 2013; 19:5343-54. [DOI: 10.1007/s00894-013-2021-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 09/22/2013] [Indexed: 10/26/2022]
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Bhardwaj P, Singh S. High pressure phase transition and elastic properties of covalent heavy rare-earth antimonides. J Mol Model 2011; 17:3057-62. [PMID: 21360178 DOI: 10.1007/s00894-011-0980-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/21/2011] [Indexed: 11/24/2022]
Abstract
In the present paper, we report an investigation into the high-pressure structural phase transition of rare earth antimonides (DySb and ErSb). A modified interaction potential model (MIPM) (including the covalency effect) has been developed. Phase transition pressures are associated with a sudden collapse in volume, indicating the occurrence of a first order phase transition. At compressed volumes, these compounds are found in the CsCl phase. The phase transition pressures and associated volume collapses obtained from the potential model developed here show a generally better agreement with available experimental data than others available in the literature. The elastic constants and bulk modulus are also reported. Our results are, in general, in good agreement with experimental and theoretical data where available, and provide predictions where data are unavailable.
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Affiliation(s)
- Purvee Bhardwaj
- High Pressure Physics Laboratory, Department of Physics, Barkatullah University, Bhopal 462026, India.
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12
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Caruso AN. The physics of solid-state neutron detector materials and geometries. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:443201. [PMID: 21403341 DOI: 10.1088/0953-8984/22/44/443201] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Detection of neutrons, at high total efficiency, with greater resolution in kinetic energy, time and/or real-space position, is fundamental to the advance of subfields within nuclear medicine, high-energy physics, non-proliferation of special nuclear materials, astrophysics, structural biology and chemistry, magnetism and nuclear energy. Clever indirect-conversion geometries, interaction/transport calculations and modern processing methods for silicon and gallium arsenide allow for the realization of moderate- to high-efficiency neutron detectors as a result of low defect concentrations, tuned reaction product ranges, enhanced effective omnidirectional cross sections and reduced electron-hole pair recombination from more physically abrupt and electronically engineered interfaces. Conversely, semiconductors with high neutron cross sections and unique transduction mechanisms capable of achieving very high total efficiency are gaining greater recognition despite the relative immaturity of their growth, lithographic processing and electronic structure understanding. This review focuses on advances and challenges in charged-particle-based device geometries, materials and associated mechanisms for direct and indirect transduction of thermal to fast neutrons within the context of application. Calorimetry- and radioluminescence-based intermediate processes in the solid state are not included.
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Affiliation(s)
- A N Caruso
- Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
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13
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Brewer JR, Gernhart Z, Liu HY, Cheung CL. Growth of [100]-Textured Gadolinium Nitride Films by CVD. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/cvde.201004288] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Senapati K, Fix T, Vickers ME, Blamire MG, Barber ZH. Magnetic exchange hardening in polycrystalline GdN thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:302003. [PMID: 21399332 DOI: 10.1088/0953-8984/22/30/302003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the observation of intrinsic exchange hardening in polycrystalline GdN thin films grown at room temperature by magnetron sputtering. We find, in addition to the ferromagnetic phase, that a fraction of GdN crystallizes in a structural polymorphic form which orders antiferromagnetically. The relative fraction of these two phases was controlled by varying the relative abundance of reactive species in the sputtering plasma by means of the sputtering power and N(2) partial pressure. An exchange bias of ∼ 30 Oe was observed at 10 K. The exchange coupling between the ferromagnetic and the antiferromagnetic phases resulted in an order of magnitude enhancement in the coercive field in these films.
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Affiliation(s)
- K Senapati
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK
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15
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Gupta DC, Kulshrestha S. Pressure induced magnetic, electronic and mechanical properties of SmX (X = Se, Te). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:436011. [PMID: 21832457 DOI: 10.1088/0953-8984/21/43/436011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The magnetic, structural, elastic and electronic properties of Sm-chalcogenides in the stable [Formula: see text] and high pressure [Formula: see text] phase have been analyzed using an ab initio pseudo-potential method with a spin-polarized GGA based on exchange-correlation energy optimization, as implemented in SIESTA code. The magnetic phase stability has been determined from the total energy calculations in non-magnetic and magnetic phases, which clearly indicate that at ambient and high pressures, these compounds are ferromagnetically stable. Also, the Sm ion is described in both five and six localized f electrons. Under compression the Sm chalcogenides undergo a first-order transformation from Sm(2+) to a stable valence state (Sm(3+)) with delocalization of the 4f electrons into the 5d states of Sm followed by a structural transition from the B1 to the B2 phase. The structural properties namely, equilibrium lattice constant, bulk modulus, its pressure derivative, transition pressure and volume collapse agree well with the experimental results. We have also computed the electronic structure at different volumes.
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Affiliation(s)
- D C Gupta
- Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior-474 011 (MP), India
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16
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Losovyj YB, Wooten D, Santana JC, An JM, Belashchenko KD, Lozova N, Petrosky J, Sokolov A, Tang J, Wang W, Arulsamy N, Dowben PA. Comparison of n-type Gd(2)O(3) and Gd-doped HfO(2). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:045602. [PMID: 21715816 DOI: 10.1088/0953-8984/21/4/045602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Gd(2)O(3) and Gd-doped HfO(2) films were deposited on p-type silicon substrates in a reducing atmosphere. Gd 4f photoexcitation peaks at roughly 7 and 5 eV below the valence band maximum have been identified using the resonant photoemission of Gd(2)O(3) and Gd-doped HfO(2) films, respectively. In the case of Gd(2)O(3), strong hybridization with the O 2p band is demonstrated, and there is evidence that the Gd 4f weighted band exhibits dispersion in the bulk band structure. The rectifying (diode-like) properties of Gd-doped HfO(2)-silicon and Gd(2)O(3)-silicon heterojunctions are demonstrated.
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Affiliation(s)
- Ya B Losovyj
- Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, PO Box 880111, Lincoln, NE 68588-0111, USA. Center for Advanced Microstructures and Devices, Louisiana State University, 6980 Jefferson Highway, Baton Rouge, LA 70806, USA
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17
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Chapter 241 The Dual, Localized or Band‐Like, Character of the 4f‐States. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s0168-1273(08)00001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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