Candice R. Forrester, Christophe Testelin, Kaushini Wickramasinghe, Ido Levy, Dominique Demaille, David Hrabovsky, Xiaxin Ding, Lia Krusin-Elbaum, Gustavo E. Lopez, Maria C. Tamargo
Tuning the properties of magnetic topological materials is of interest to realize exotic physical phenomena, new quantum phases and quasiparticles, and topological spintronic devices. However, current topological materials exhibit Curie temperature (TC) values far below those needed for practical applications. In recent years, significant progress has been made to control and optimize TC, particularly through defect-engineering of these structures. Most recently, we reported TC values up to 80 K for (MnSb2Te4)x(Sb2Te3)1−x when 0.7 ≤ x ≤ 0.85 by controlling the composition x and the Mn content in these structures during molecular beam epitaxy growth. In this study, we show further enhancement of the TC, as high as 100 K, by maintaining high Mn content and reducing the growth rate from 0.9 nm/min to 0.5 nm/min. Derivative curves of the Hall resistance and the magnetization reveal the presence of two TC components contributing to the overall value and suggest TC1 and TC2 have distinct origins: excess Mn in MnSb2Te4 septuple layers (SLs) and high Mn content in Sb2−yMnyTe3 quintuple layer (QL) alloys, respectively. To elucidate the mechanisms promoting higher TC values in this system, we show evidence of enhanced structural disorder due to the excess Mn that occupies not only Sb sites but also Te sites, leading to the formation of a new crystal structure for these materials. Learning to control defects that enhance desired magnetic properties and understanding the mechanisms that promote high TC in magnetic topological materials such as (Mn1+ySb2−yTe4)x(Sb2−yMnyTe3)1−x is of great importance to achieve practical quantum devices.
{"title":"Structural and magnetic properties of molecular beam epitaxy (MnSb2Te4)x(Sb2Te3)1−x topological materials with exceedingly high Curie temperature","authors":"Candice R. Forrester, Christophe Testelin, Kaushini Wickramasinghe, Ido Levy, Dominique Demaille, David Hrabovsky, Xiaxin Ding, Lia Krusin-Elbaum, Gustavo E. Lopez, Maria C. Tamargo","doi":"10.1063/5.0195940","DOIUrl":"https://doi.org/10.1063/5.0195940","url":null,"abstract":"Tuning the properties of magnetic topological materials is of interest to realize exotic physical phenomena, new quantum phases and quasiparticles, and topological spintronic devices. However, current topological materials exhibit Curie temperature (TC) values far below those needed for practical applications. In recent years, significant progress has been made to control and optimize TC, particularly through defect-engineering of these structures. Most recently, we reported TC values up to 80 K for (MnSb2Te4)x(Sb2Te3)1−x when 0.7 ≤ x ≤ 0.85 by controlling the composition x and the Mn content in these structures during molecular beam epitaxy growth. In this study, we show further enhancement of the TC, as high as 100 K, by maintaining high Mn content and reducing the growth rate from 0.9 nm/min to 0.5 nm/min. Derivative curves of the Hall resistance and the magnetization reveal the presence of two TC components contributing to the overall value and suggest TC1 and TC2 have distinct origins: excess Mn in MnSb2Te4 septuple layers (SLs) and high Mn content in Sb2−yMnyTe3 quintuple layer (QL) alloys, respectively. To elucidate the mechanisms promoting higher TC values in this system, we show evidence of enhanced structural disorder due to the excess Mn that occupies not only Sb sites but also Te sites, leading to the formation of a new crystal structure for these materials. Learning to control defects that enhance desired magnetic properties and understanding the mechanisms that promote high TC in magnetic topological materials such as (Mn1+ySb2−yTe4)x(Sb2−yMnyTe3)1−x is of great importance to achieve practical quantum devices.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141613066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eric Viklund, David N. Seidman, Sam Posen, Brad M. Tennis, Grigory Eremeev
Despite having advantageous superconducting properties, Nb3Sn superconducting radiofrequency (SRF) cavities still have practical challenges compared to Nb SRF cavities due to the brittle nature of Nb3Sn. Performance degradation can occur when an Nb3Sn SRF cavity experiences mechanical stresses, such as during handling and tuning of the cavity. In this study, we present a potential treatment for SRF cavities that have experienced stress-induced performance degradation that involves a recoating procedure. The degraded cavity is coated with a small amount of Sn using a single-step vapor-diffusion methodology. Using this approach, we can recover a significant portion of the lost performance of the Nb3Sn SRF cavity.
{"title":"Healing gradient degradation in Nb3Sn SRF cavities using a recoating method","authors":"Eric Viklund, David N. Seidman, Sam Posen, Brad M. Tennis, Grigory Eremeev","doi":"10.1063/5.0218739","DOIUrl":"https://doi.org/10.1063/5.0218739","url":null,"abstract":"Despite having advantageous superconducting properties, Nb3Sn superconducting radiofrequency (SRF) cavities still have practical challenges compared to Nb SRF cavities due to the brittle nature of Nb3Sn. Performance degradation can occur when an Nb3Sn SRF cavity experiences mechanical stresses, such as during handling and tuning of the cavity. In this study, we present a potential treatment for SRF cavities that have experienced stress-induced performance degradation that involves a recoating procedure. The degraded cavity is coated with a small amount of Sn using a single-step vapor-diffusion methodology. Using this approach, we can recover a significant portion of the lost performance of the Nb3Sn SRF cavity.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrew Venzie, Michael Stavola, W. Beall Fowler, Evan R. Glaser, Marko J. Tadjer, Jason I. Forbus, Mary Ellen Zvanut, Stephen J. Pearton
Hydrogen in β-Ga2O3 passivates shallow impurities and deep-level defects and can have a strong effect on conductivity. More than a dozen O–D vibrational lines have been reported for β-Ga2O3 treated with the heavy isotope of hydrogen, deuterium. To explain the large number of O–D centers that have been observed, the involvement of additional nearby defects and impurities has been proposed. A few O–H centers have been associated with specific impurities that were introduced intentionally during crystal growth. However, definitive assignments of O–H and O–D vibrational lines associated with important adventitious impurities, such as Si and Fe, have been difficult. A set of well-characterized Si-doped β-Ga2O3 epitaxial layers with different layer thicknesses has been deuterated and investigated by vibrational spectroscopy to provide new evidence for the assignment of a line at 2577 cm−1 to an OD–Si complex. The vibrational properties of several of the reported OD-impurity complexes are consistent with the existence of a family of defects with a VGa1ic−D center at their core that is perturbed by a nearby impurity.
{"title":"Assignments of vibrational lines to OD-impurity complexes for adventitious impurities in β-Ga2O3","authors":"Andrew Venzie, Michael Stavola, W. Beall Fowler, Evan R. Glaser, Marko J. Tadjer, Jason I. Forbus, Mary Ellen Zvanut, Stephen J. Pearton","doi":"10.1063/5.0219979","DOIUrl":"https://doi.org/10.1063/5.0219979","url":null,"abstract":"Hydrogen in β-Ga2O3 passivates shallow impurities and deep-level defects and can have a strong effect on conductivity. More than a dozen O–D vibrational lines have been reported for β-Ga2O3 treated with the heavy isotope of hydrogen, deuterium. To explain the large number of O–D centers that have been observed, the involvement of additional nearby defects and impurities has been proposed. A few O–H centers have been associated with specific impurities that were introduced intentionally during crystal growth. However, definitive assignments of O–H and O–D vibrational lines associated with important adventitious impurities, such as Si and Fe, have been difficult. A set of well-characterized Si-doped β-Ga2O3 epitaxial layers with different layer thicknesses has been deuterated and investigated by vibrational spectroscopy to provide new evidence for the assignment of a line at 2577 cm−1 to an OD–Si complex. The vibrational properties of several of the reported OD-impurity complexes are consistent with the existence of a family of defects with a VGa1ic−D center at their core that is perturbed by a nearby impurity.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141588333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Sutar, D. Grabnar, D. Vengust, D. Svetin, E. Goreshnik, D. Mihailovic, T. Mertelj
We investigated temperature (T) and excitation density dependent ultrafast near-infrared (NIR) transient reflectivity dynamics in the charge density wave (CDW) phases of bulk layered 1T-VSe2 using NIR and visible excitations. The data reveal fingerprints of conventional non-adiabatic CDW collective dynamics with rather fast electronic order parameter dynamics showing sub-picosecond suppression and recovery. The slower T-dependent 100-ps dynamics indicates rather isotropic heat transport dominated by the lattice degrees of freedom.
{"title":"Photo-induced collective charge-density-wave dynamics in bulk 1T-VSe2","authors":"P. Sutar, D. Grabnar, D. Vengust, D. Svetin, E. Goreshnik, D. Mihailovic, T. Mertelj","doi":"10.1063/5.0204205","DOIUrl":"https://doi.org/10.1063/5.0204205","url":null,"abstract":"We investigated temperature (T) and excitation density dependent ultrafast near-infrared (NIR) transient reflectivity dynamics in the charge density wave (CDW) phases of bulk layered 1T-VSe2 using NIR and visible excitations. The data reveal fingerprints of conventional non-adiabatic CDW collective dynamics with rather fast electronic order parameter dynamics showing sub-picosecond suppression and recovery. The slower T-dependent 100-ps dynamics indicates rather isotropic heat transport dominated by the lattice degrees of freedom.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Among today’s bustling lifestyles, the demand for autonomous, durable, and low-maintenance healthcare systems has surged, surpassing that of earlier periods. Nanostructured and environmentally friendly materials employed in nanogenerator technology offer a novel avenue for biomedical applications by harnessing biomechanical energy. Triboelectric Nanogenerators (TENGs) have emerged as comprehensive solutions, furnishing self-sustaining, eco-conscious, and compact devices. Recognizing the immense potential of TENGs, this paper presents a comprehensive overview of its motion detection. Our analysis delves into the versatility of TENG-based motion detection systems, providing wearable, user-friendly solutions powered by human motion. Recent advancements in triboelectric devices are cataloged, elucidating their structural intricacies, capabilities, performance metrics, and future prospects. In addition, the article also outlines the applications of different TENGs in motion monitoring, including contact, non-contact, and single-electrode mode. The evolution of intelligent wearable technologies has extended our capacities in communication, healthcare, and various other domains beyond our biological limits. Apart from the Internet of Things, the concept of Internet of bodies or beings is poised for rapid advancement, promising further transformation of our lifestyles. Conclusively, we present insights into forthcoming opportunities and plausible strategies to address anticipated hurdles.
在当今熙熙攘攘的生活方式中，人们对自主、耐用、低维护的医疗保健系统的需求激增，超过了早期的需求。纳米发电机技术所采用的纳米结构和环保材料通过利用生物机械能，为生物医学应用提供了一条新途径。三电纳米发电机（TENGs）已成为一种全面的解决方案，可提供自我维持、具有生态意识和结构紧凑的设备。认识到 TENG 的巨大潜力，本文对其运动检测进行了全面概述。我们的分析深入探讨了基于 TENG 的运动检测系统的多功能性，提供了由人体运动驱动的可穿戴、用户友好型解决方案。本文介绍了三电装置的最新进展，阐明了其结构的复杂性、功能、性能指标和未来前景。此外，文章还概述了不同 TENG 在运动监测中的应用，包括接触式、非接触式和单电极模式。智能可穿戴技术的发展拓展了我们在通信、医疗保健和其他各个领域的能力，超越了我们的生理极限。除物联网外，身体或生命互联网的概念也在快速发展，有望进一步改变我们的生活方式。最后，我们对即将到来的机遇和解决预期障碍的可行战略提出了见解。
{"title":"Application of triboelectric nanogenerator in self-powered motion detection devices: A review","authors":"Hongyuan Jiang, Xin Lv, Kai Wang","doi":"10.1063/5.0219633","DOIUrl":"https://doi.org/10.1063/5.0219633","url":null,"abstract":"Among today’s bustling lifestyles, the demand for autonomous, durable, and low-maintenance healthcare systems has surged, surpassing that of earlier periods. Nanostructured and environmentally friendly materials employed in nanogenerator technology offer a novel avenue for biomedical applications by harnessing biomechanical energy. Triboelectric Nanogenerators (TENGs) have emerged as comprehensive solutions, furnishing self-sustaining, eco-conscious, and compact devices. Recognizing the immense potential of TENGs, this paper presents a comprehensive overview of its motion detection. Our analysis delves into the versatility of TENG-based motion detection systems, providing wearable, user-friendly solutions powered by human motion. Recent advancements in triboelectric devices are cataloged, elucidating their structural intricacies, capabilities, performance metrics, and future prospects. In addition, the article also outlines the applications of different TENGs in motion monitoring, including contact, non-contact, and single-electrode mode. The evolution of intelligent wearable technologies has extended our capacities in communication, healthcare, and various other domains beyond our biological limits. Apart from the Internet of Things, the concept of Internet of bodies or beings is poised for rapid advancement, promising further transformation of our lifestyles. Conclusively, we present insights into forthcoming opportunities and plausible strategies to address anticipated hurdles.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reducing dimensionality can induce profound modifications to the physical properties of a system. In two-dimensional TaS2 and TaSe2, the charge-density wave phase accompanies a Mott transition, thus realizing the strongly correlated insulating state. However, this scenario deviates from TaTe2 due to p–d hybridization, resulting in a substantial contribution of Te 5p at the Fermi level. Here, we show that, differently from the Mott insulating phase of its sister compounds, bilayer TaTe2 hosts a power-law (V-shaped) gap at the Fermi level reminiscent of a Coulomb gap. It suggests the possible role of unscreened long-range Coulomb interactions emerging in lowered dimensions, potentially coupled with a disordered short-range charge-density wave. Our findings reveal the importance of long-range interactions sensitive to interlayer screening, providing another venue for the interplay of complex quantum phenomena in two-dimensional materials.
{"title":"Dimensionality-driven power-law gap in the bilayer TaTe2 grown by molecular-beam epitaxy","authors":"Bruno Kenichi Saika, Satoshi Yoshida, Markel Pardo-Almanza, Natsuki Mitsuishi, Masato Sakano, Yuita Fujisawa, Yue Wang, Yoshihiro Iwasa, Hideki Matsuoka, Hidefumi Takahashi, Shintaro Ishiwata, Yoshinori Okada, Masaki Nakano, Kyoko Ishizaka","doi":"10.1063/5.0213957","DOIUrl":"https://doi.org/10.1063/5.0213957","url":null,"abstract":"Reducing dimensionality can induce profound modifications to the physical properties of a system. In two-dimensional TaS2 and TaSe2, the charge-density wave phase accompanies a Mott transition, thus realizing the strongly correlated insulating state. However, this scenario deviates from TaTe2 due to p–d hybridization, resulting in a substantial contribution of Te 5p at the Fermi level. Here, we show that, differently from the Mott insulating phase of its sister compounds, bilayer TaTe2 hosts a power-law (V-shaped) gap at the Fermi level reminiscent of a Coulomb gap. It suggests the possible role of unscreened long-range Coulomb interactions emerging in lowered dimensions, potentially coupled with a disordered short-range charge-density wave. Our findings reveal the importance of long-range interactions sensitive to interlayer screening, providing another venue for the interplay of complex quantum phenomena in two-dimensional materials.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141532143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dante J. O’Hara, Hsun-Jen Chuang, Kathleen M. McCreary, Mehmet A. Noyan, Sung-Joon Lee, Enrique D. Cobas, Berend T. Jonker
The van der Waals material hexagonal boron nitride (hBN) has emerged as a promising candidate for hosting room temperature single-photon emitters (SPEs) for next-generation quantum technologies. However, the requirement of a high temperature anneal (850 °C or higher) to activate the SPEs in hBN makes it difficult to integrate into hybrid structures that cannot tolerate such temperatures, including all silicon-based circuits. In this work, we present a method to deterministically activate quantum emitters in multilayered hBN on a process substrate, followed by a zero thermal budget transfer to a target substrate. This technique does not lead to any degradation or loss of photon purity in the hBN emitters and provides a procedure for combining high-purity emitters with other exciting photonic, magnetic, or electrical properties to explore new physical phenomena. The ability to transfer hBN emitters onto arbitrary substrates creates new technological possibilities to incorporate these quantum photonic properties into photonic integrated circuits and plasmonic devices.
{"title":"Transfer of hexagonal boron nitride quantum emitters onto arbitrary substrates with zero thermal budget","authors":"Dante J. O’Hara, Hsun-Jen Chuang, Kathleen M. McCreary, Mehmet A. Noyan, Sung-Joon Lee, Enrique D. Cobas, Berend T. Jonker","doi":"10.1063/5.0218367","DOIUrl":"https://doi.org/10.1063/5.0218367","url":null,"abstract":"The van der Waals material hexagonal boron nitride (hBN) has emerged as a promising candidate for hosting room temperature single-photon emitters (SPEs) for next-generation quantum technologies. However, the requirement of a high temperature anneal (850 °C or higher) to activate the SPEs in hBN makes it difficult to integrate into hybrid structures that cannot tolerate such temperatures, including all silicon-based circuits. In this work, we present a method to deterministically activate quantum emitters in multilayered hBN on a process substrate, followed by a zero thermal budget transfer to a target substrate. This technique does not lead to any degradation or loss of photon purity in the hBN emitters and provides a procedure for combining high-purity emitters with other exciting photonic, magnetic, or electrical properties to explore new physical phenomena. The ability to transfer hBN emitters onto arbitrary substrates creates new technological possibilities to incorporate these quantum photonic properties into photonic integrated circuits and plasmonic devices.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141532144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Hensling, W. Braun, D. Y. Kim, L. Majer, S. Smink, B. D. Faeth, J. Mannhart
{"title":"Erratum: “State of the art, trends, and opportunities for oxide epitaxy” [APL Mater. 12, 040902 (2024)]","authors":"F. Hensling, W. Braun, D. Y. Kim, L. Majer, S. Smink, B. D. Faeth, J. Mannhart","doi":"10.1063/5.0222730","DOIUrl":"https://doi.org/10.1063/5.0222730","url":null,"abstract":"","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141704650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zixin Fan, Qiangtao Sui, Feng Ran, Haoming Ling, Dingyi Li, Zihao Wang, Pan Chen, Yan Liang, Jiandi Zhang
Recently, KTaO3 (KTO)-based 5d two-dimensional electron gases (2DEGs), characterized by robust spin–orbit coupling, have emerged as promising candidates for future spintronic devices. However, the carrier mobility of KTO-based 2DEGs is typically lower than that of SrTiO3-based 2DEGs, which limits their further development. It is imperative to explore the underlying causes of diminished carrier mobility and devise strategies to augment it. In addition, the genesis of magnetism within KTO-based 2DEGs remains ambiguous. In this study, the 2DEG within the amorphous-EuTiO3/KTO (a-ETO/KTO) heterostructure demonstrates a high electron mobility of 289.1 cm2 V−1 s−1, which exhibits a significant decrease as the film growth temperatures increase. This decrease can be primarily ascribed to electron scattering by impurities, which is induced by the amplified interfacial element interdiffusion at a higher film growth temperature. In addition, the magnetism of 2DEGs for samples grown at different temperatures shows an increasing trend with growth temperatures, which is predominantly derived from the interdiffusion of Eu atoms. This study provides an in-depth analysis of the origin of magnetic ordering and reduced mobility in KTO-based 2DEGs, which will promote the further development of 2DEGs for future applications in electronic devices.
最近，以 KTaO3（KTO）为基础的五维二维电子气体（2DEG）以强大的自旋轨道耦合为特征，成为未来自旋电子器件的理想候选材料。然而，基于 KTO 的二维电子气体的载流子迁移率通常低于基于 SrTiO3 的二维电子气体，这限制了它们的进一步发展。当务之急是探索载流子迁移率降低的根本原因，并制定增强载流子迁移率的策略。此外，KTO 基 2DEG 内磁性的成因仍不明确。在这项研究中，非晶-EuTiO3/KTO（a-ETO/KTO）异质结构中的 2DEG 显示出 289.1 cm2 V-1 s-1 的高电子迁移率，但随着薄膜生长温度的升高，迁移率显著降低。这种下降主要是由于杂质引起的电子散射，而在较高的薄膜生长温度下，杂质会放大界面元素的相互扩散。此外，在不同温度下生长的样品的二维电子元件的磁性随着生长温度的升高呈上升趋势，这主要源于 Eu 原子的相互扩散。本研究深入分析了基于 KTO 的二维电子元件的磁有序性和迁移率降低的原因，这将促进二维电子元件的进一步发展，使其在未来的电子器件中得到应用。
{"title":"The origin of magnetic ordering and reduced mobility in KTaO3-based 2DEGs: Interfacial interdiffusion","authors":"Zixin Fan, Qiangtao Sui, Feng Ran, Haoming Ling, Dingyi Li, Zihao Wang, Pan Chen, Yan Liang, Jiandi Zhang","doi":"10.1063/5.0206068","DOIUrl":"https://doi.org/10.1063/5.0206068","url":null,"abstract":"Recently, KTaO3 (KTO)-based 5d two-dimensional electron gases (2DEGs), characterized by robust spin–orbit coupling, have emerged as promising candidates for future spintronic devices. However, the carrier mobility of KTO-based 2DEGs is typically lower than that of SrTiO3-based 2DEGs, which limits their further development. It is imperative to explore the underlying causes of diminished carrier mobility and devise strategies to augment it. In addition, the genesis of magnetism within KTO-based 2DEGs remains ambiguous. In this study, the 2DEG within the amorphous-EuTiO3/KTO (a-ETO/KTO) heterostructure demonstrates a high electron mobility of 289.1 cm2 V−1 s−1, which exhibits a significant decrease as the film growth temperatures increase. This decrease can be primarily ascribed to electron scattering by impurities, which is induced by the amplified interfacial element interdiffusion at a higher film growth temperature. In addition, the magnetism of 2DEGs for samples grown at different temperatures shows an increasing trend with growth temperatures, which is predominantly derived from the interdiffusion of Eu atoms. This study provides an in-depth analysis of the origin of magnetic ordering and reduced mobility in KTO-based 2DEGs, which will promote the further development of 2DEGs for future applications in electronic devices.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141532145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Gray, Kadaba Swathi, Dundappa Mumbaraddi, Timothy W. Carlson, G. Marcus, David Carroll
In this work, we present a solvothermal, in situ doping methodology for synthesizing crystalline doped 2D bismuth telluride (Bi2Te3) nanoplates. Isoelectronic antimony (Sb) substitution at the bismuth (Bi) site is chosen to minimize the lattice strain in the nanostructure. Using a combination of x-ray techniques and electron microscopy, we demonstrate that the rhombohedral crystal structure (space group R3̄m), characteristic of Bi2Te3 is preserved in few-quintuple-layer, hexagonal nanoplates. Our findings reveal a uniform dispersion of Sb within the nanoplates up to an atomic concentration of 1%. Beyond this threshold, a disordered SbTe alloy begins to form along the crystal edges in addition to Sb substitution at the Bi sites in the bulk, restricting further growth of the nanoplates. In addition, we examine the different stresses that develop within the nanoplates as lattice strain increases due to Sb substitution. This study provides fundamental insights into the dopant’s effect on the self-assembled growth of electronically relevant 2D crystals.
在这项工作中，我们提出了一种溶热原位掺杂方法，用于合成晶体掺杂二维碲化铋（Bi2Te3）纳米板。在铋（Bi）位点上选择等电子锑（Sb）取代，以最大限度地减少纳米结构中的晶格应变。通过结合使用 X 射线技术和电子显微镜，我们证明 Bi2Te3 所特有的斜方晶体结构（空间群 R3̄m）在少五层六边形纳米板中得以保留。我们的研究结果表明，在原子浓度不超过 1%的纳米板中，锑的分散是均匀的。超过这一阈值后，除了在块体的铋位点形成锑替代外，沿着晶体边缘开始形成无序的锑碲合金，从而限制了纳米板的进一步生长。此外，我们还研究了随着 Sb 置换导致晶格应变增加，纳米板内部产生的不同应力。这项研究从根本上揭示了掺杂剂对电子相关二维晶体自组装生长的影响。
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