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Szary MJ. Rashba effect: a chemical physicist's approach. Phys Chem Chem Phys 2023; 25:30099-30115. [PMID: 37920992 DOI: 10.1039/d3cp04242a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Understanding the mechanisms underlying the emergence of giant spin splitting (GSS) is fundamental in the pursuit of more robust strategies for designing materials with desired spin splitting. This drive for material innovation continues to captivate a burgeoning community of early-career researchers with backgrounds in chemistry and material science. However, new to the field, they are often equipped only with the insight provided by the original Bychkov-Rashba model. Furthermore, daunted by the tight-binding perspective on the non-vanishing orbital angular momentum (OAM), they struggle to accurately account for the atomic spin-orbit interaction (SOI) in the formation of GSS. To address these challenges and equip young chemists with better-suited tools, this review aims to provide a more intuitive perspective on atomic interactions (orbital hybridization), structure symmetry, and atomic SOI in the formation of GSS. In pursuit of this goal, the review explores the Bychkov-Rashba model, its advantages, and limitations. Subsequently, it introduces the orbital framework, wherein GSS is modulated by atomic SOI and the interplay of OAM with the surface electrostatic field. Given the explicit dependence of both these factors on OAM, the review examines why OAM is typically quenched in crystal structures and how chemical bonds involving different orbital types can lead to its non-zero values in the presence of inversion symmetry breaking. Finally, with this chemistry-focused perspective, the review examines the rise of GSS in selected examples.
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Affiliation(s)
- Maciej J Szary
- Institute of Physics, Poznan University of Technology, ul. Piotrowo 3, 61-138 Poznan, Poland.
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Yang S, Liu K, Xu Y, Liu L, Li H, Zhai T. Gate Dielectrics Integration for 2D Electronics: Challenges, Advances, and Outlook. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207901. [PMID: 36226584 DOI: 10.1002/adma.202207901] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/28/2022] [Indexed: 05/05/2023]
Abstract
2D semiconductors have emerged both as an ideal platform for fundamental studies and as promising channel materials in beyond-silicon field-effect-transistors due to their outstanding electrical properties and exceptional tunability via external field. However, the lack of proper dielectrics for 2D semiconductors has become a major roadblock for their further development toward practical applications. The prominent issues between conventional 3D dielectrics and 2D semiconductors arise from the integration and interface quality, where defect states and imperfections lead to dramatic deterioration of device performance. In this review article, the root causes of such issues are briefly analyzed and recent advances on some possible solutions, including various approaches of adapting conventional dielectrics to 2D semiconductors, and the development of novel dielectrics with van der Waals surface toward high-performance 2D electronics are summarized. Then, in the perspective, the requirements of ideal dielectrics for state-of-the-art 2D devices are outlined and an outlook for their future development is provided.
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Affiliation(s)
- Sijie Yang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Kailang Liu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Yongshan Xu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Lixin Liu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Huiqiao Li
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
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Tiwari RP. Enhanced shift current bulk photovoltaic effect in ferroelectric Rashba semiconductor α-GeTe: ab initiostudy from three- to two-dimensional van der Waals layered structures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:435404. [PMID: 35985305 DOI: 10.1088/1361-648x/ac8b50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
The ferroelectric Rashba semiconductors (FERSCs) are endowed with a unique combination of ferroelectricity and the spin degree of freedom, resulting in a long carrier lifetime and impressive bulk photovoltaic (BPV) efficiency that reached 25% in organometal halide perovskites. The BPV efficiency can be further improved by using low-dimensional ferroelectrics however, it is inhibited by the ferroelectric instability in low-dimensional perovskites and toxicity along with phase instability of the lead-halide perovskites. To address these challenges, theα-GeTe could be of great importance which is the simplest known lead-free FERSC with an intrinsic layered structure. Therefore, in this work, we investigate the BPV properties of three- to two-dimensional van der Waals structures ofα-GeTe by calculating the shift current (SHC). We predict that the mono (1.56 Å) and bi-layers (5.44-6.14 Å)α-GeTe with the buckled honeycomb structure are dynamically stable and possess the characteristic features of the bulk up to the nanoscale limit. The SHC of ∼70μA V-2is calculated in bulk α-GeTe which is 20 times larger than that obtained in organometal halides in the visible light. The SHC increases with decreasing the number of layers, reaching a maximum amplitude of ∼300μA V-2at 2.67 eV in the monolayer which is more than double that obtained in monolayer GeS. We find that the SHC in monolayer α-GeTe can be further enhanced and redshifted by applying a compressive strain; which is correlated with the strong absorption of thexx-polarized light, stimulated by the more delocalized px/yorbital character of the density of states. Furthermore, in the bilayer structures, the magnitude of the SHC is sensitive to the layers' stacking arrangement and a maximum SHC (∼250μA V-2) can be achieved with an AB-type stacking arrangement. Combining these results with the benefits of being environmental-friendly material makesα-GeTe a good candidate for next-generation solar cells application.
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Lafalce E, Amerling E, Yu ZG, Sercel PC, Whittaker-Brooks L, Vardeny ZV. Rashba splitting in organic-inorganic lead-halide perovskites revealed through two-photon absorption spectroscopy. Nat Commun 2022; 13:483. [PMID: 35078984 PMCID: PMC8789784 DOI: 10.1038/s41467-022-28127-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/10/2022] [Indexed: 11/30/2022] Open
Abstract
The Rashba splitting in hybrid organic-inorganic lead-halide perovskites (HOIP) is particularly promising and yet controversial, due to questions surrounding the presence or absence of inversion symmetry. Here we utilize two-photon absorption spectroscopy to study inversion symmetry breaking in different phases of these materials. This is an all-optical technique to observe and quantify the Rashba effect as it probes the bulk of the materials. In particular, we measure two-photon excitation spectra of the photoluminescence in 2D, 3D, and anionic mixed HOIP crystals, and show that an additional band above, but close to the optical gap is the signature of new two-photon transition channels that originate from the Rashba splitting. The inversion symmetry breaking is believed to arise from ionic impurities that induce local electric fields. The observation of the Rashba splitting in the bulk of HOIP has significant implications for the understanding of their spintronic and optoelectronic device properties.
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Affiliation(s)
- Evan Lafalce
- Department of Physics & Astronomy, University of Utah, Salt Lake City, UT, 84112, USA
| | - Eric Amerling
- Department of Chemistry, University of Utah, Salt Lake City, UT, 84112, USA
| | - Zhi-Gang Yu
- Sivananthan Laboratories, Bolingbrook, IL, 60440, USA
| | - Peter C Sercel
- Center for Hybrid Organic Inorganic Semiconductors for Energy, 15013 Denver West Parkway, Golden, CO, 80401, USA
| | | | - Z Valy Vardeny
- Department of Physics & Astronomy, University of Utah, Salt Lake City, UT, 84112, USA.
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5
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Flux periodic oscillations and phase-coherent transport in GeTe nanowire-based devices. Nat Commun 2021; 12:754. [PMID: 33531502 PMCID: PMC7854721 DOI: 10.1038/s41467-021-21042-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/05/2021] [Indexed: 11/09/2022] Open
Abstract
Despite the fact that GeTe is known to be a very interesting material for applications in thermoelectrics and for phase-change memories, the knowledge on its low-temperature transport properties is only limited. We report on phase-coherent phenomena in the magnetotransport of GeTe nanowires. From universal conductance fluctuations measured on GeTe nanowires with Au contacts, a phase-coherence length of about 280 nm at 0.5 K is determined. The distinct phase-coherence is confirmed by the observation of Aharonov-Bohm type oscillations for parallel magnetic fields. We interpret the occurrence of these magnetic flux-periodic oscillations by the formation of a tubular hole accumulation layer. For Nb/GeTe-nanowire/Nb Josephson junctions we obtained a critical current of 0.2 μA at 0.4 K. By applying a perpendicular magnetic field the critical current decreases monotonously with increasing field, whereas in a parallel field the critical current oscillates with a period of the magnetic flux quantum confirming the presence of a tubular hole channel.
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Béland VA, Ragogna PJ. Metallized Phosphane-Ene Polymer Networks as Precursors for Ceramics with Excellent Shape Retention. ACS APPLIED MATERIALS & INTERFACES 2020; 12:27640-27650. [PMID: 32441913 DOI: 10.1021/acsami.0c09044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Our research group has reported the synthesis of phosphane-ene photopolymer networks, where the networks are composed of cross-linked tertiary alkyl phosphines. Taking advantage of the rich coordination chemistry of alkyl phosphines and the material's susceptibility to solution chemistry, we were able to generate Co, Al, and Ge macromolecular adducts. The metallized polymer networks can be pyrolyzed to make metal-doped carbon, commodity materials in the areas of battery, and fuel cell research. The polymer precursors can also be shaped by spin coating and lithography, before being metallized and pyrolyzed to give patterned ceramics, which display excellent shape retention of the original patterns.
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Affiliation(s)
- Vanessa A Béland
- Department of Chemistry and the Center for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Paul J Ragogna
- Department of Chemistry and the Center for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, London, Ontario N6A 5B7, Canada
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Xin JZ, Fu CG, Shi WJ, Li GW, Auffermann G, Qi YP, Zhu TJ, Zhao XB, Felser C. Synthesis and thermoelectric properties of Rashba semiconductor BiTeBr with intensive texture. RARE METALS 2018; 37:274-281. [PMID: 29670321 PMCID: PMC5895669 DOI: 10.1007/s12598-018-1027-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/10/2018] [Accepted: 03/12/2018] [Indexed: 06/02/2023]
Abstract
Bismuth tellurohalides with Rashba-type spin splitting exhibit unique Fermi surface topology and are developed as promising thermoelectric materials. However, BiTeBr, which belongs to this class of materials, is rarely investigated in terms of the thermoelectric transport properties. In the study, polycrystalline bulk BiTeBr with intensive texture was synthesized via spark plasma sintering (SPS). Additionally, its thermoelectric properties above room temperature were investigated along both the in-plane and out-plane directions, and they exhibit strong anisotropy. Low sound velocity along two directions is found and contributes to its low lattice thermal conductivity. Polycrystalline BiTeBr exhibits relatively good thermoelectric performance along the in-plane direction, with a maximum dimensionless figure of merit (ZT) of 0.35 at 560 K. Further enhancements of ZT are expected by utilizing systematic optimization strategies.
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Affiliation(s)
- Jia-Zhan Xin
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Chen-Guang Fu
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Wu-Jun Shi
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 200031 China
| | - Guo-Wei Li
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Gudrun Auffermann
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Yan-Peng Qi
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Tie-Jun Zhu
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Xin-Bing Zhao
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
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Wlaźlak E, Blachecki A, Bisztyga-Szklarz M, Klejna S, Mazur T, Mech K, Pilarczyk K, Przyczyna D, Suchecki M, Zawal P, Szaciłowski K. Heavy pnictogen chalcohalides: the synthesis, structure and properties of these rediscovered semiconductors. Chem Commun (Camb) 2018; 54:12133-12162. [DOI: 10.1039/c8cc05149f] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Heavy pnictogen chalcohalides offer various shades from the same palette, like “Paysage” by Nicolas de Staël. Their versatility and tunability lead to a new world of possible applications.
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Affiliation(s)
- Ewelina Wlaźlak
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
- Jagiellonian University
- Faculty of Chemistry
| | - Andrzej Blachecki
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
- AGH University of Science and Technology, Faculty of Non-Ferrous Metals
- 30-059 Krakow
| | - Magdalena Bisztyga-Szklarz
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
| | - Sylwia Klejna
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
| | - Tomasz Mazur
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
| | - Krzysztof Mech
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
| | - Kacper Pilarczyk
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
| | - Dawid Przyczyna
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science
- 30-059 Krakow
| | - Maciej Suchecki
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science
- 30-059 Krakow
| | - Piotr Zawal
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science
- 30-059 Krakow
| | - Konrad Szaciłowski
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology
- 30-059 Krakow
- Poland
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Kepenekian M, Even J. Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin-Orbitronics. J Phys Chem Lett 2017; 8:3362-3370. [PMID: 28661150 DOI: 10.1021/acs.jpclett.7b01015] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In halide hybrid organic-inorganic perovskites (HOPs), spin-orbit coupling (SOC) presents a well-documented large influence on band structure. However, SOC may also present more exotic effects, such as Rashba and Dresselhaus couplings. In this Perspective, we start by recalling the main features of this effect and what makes HOP materials ideal candidates for the generation and tuning of spin-states. Then, we detail the main spectroscopy techniques able to characterize these effects and their application to HOPs. Finally, we discuss potential applications in spintronics and in spin-orbitronics in those nonmagnetic systems, which would complete the skill set of HOPs and perpetuate their ride on the crest of the wave of popularity started with optoelectronics and photovoltaics.
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Affiliation(s)
- Mikaël Kepenekian
- Institut des Sciences Chimiques de Rennes, UMR 6226, CNRS - Université de Rennes 1, 35700 Rennes, France
| | - Jacky Even
- Fonctions Optiques pour les Technologies de l'Information (FOTON), INSA de Rennes, CNRS, UMR 6082, 35708 Rennes, France
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