Pub Date : 2024-08-08DOI: 10.1007/s44214-024-00060-6
F. Tang, Xiangang Wan
{"title":"Group-theoretical study of band nodes and the emanating nodal structures in crystalline materials","authors":"F. Tang, Xiangang Wan","doi":"10.1007/s44214-024-00060-6","DOIUrl":"https://doi.org/10.1007/s44214-024-00060-6","url":null,"abstract":"","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":"29 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
FeSe is one of the most enigmatic superconductors. Among the family of iron-based compounds, it has the simplest chemical makeup and structure, and yet it displays superconducting transition temperature ( ) spanning 0 to 15 K for thin films, while it is typically 8 K for single crystals. This large variation of within one family underscores a key challenge associated with understanding superconductivity in iron chalcogenides. Here, using a dual-beam pulsed laser deposition (PLD) approach, we have fabricated a unique lattice-constant gradient thin film of FeSe which has revealed a clear relationship between the atomic structure and the superconducting transition temperature for the first time. The dual-beam PLD that generates laser fluence gradient inside the plasma plume has resulted in a continuous variation in distribution of edge dislocations within a single film, and a precise correlation between the lattice constant and has been observed here, namely, , where c is the c-axis lattice constant (and is a constant). This explicit relation in conjunction with a theoretical investigation indicates that it is the shifting of the orbital of Fe which plays a governing role in the interplay between nematicity and superconductivity in FeSe.
Supplementary information: The online version contains supplementary material available at 10.1007/s44214-024-00058-0.
FeSe 是最神秘的超导体之一。在铁基化合物家族中,它的化学组成和结构最简单,但它的薄膜超导转变温度(T c)却在 0 到 15 K 之间,而单晶体的温度通常为 8 K。一个家族中 T c 的巨大差异凸显了了解铁铬镓化合物超导性的关键挑战。在这里,我们利用双光束脉冲激光沉积(PLD)方法,制造出了一种独特的晶格恒定梯度硒化铁薄膜,首次揭示了原子结构与超导转变温度之间的明确关系。在等离子体羽流内部产生激光通量梯度的双光束 PLD 使单层薄膜内的边缘位错分布发生了连续变化,并在此观察到了晶格常数与 T c 之间的精确相关性,即 T c ∝ c - c 0,其中 c 为 c 轴晶格常数(c 0 为常数)。这种明确的关系与理论研究相结合表明,铁的 d xy 轨道移动在 FeSe 的向列性与超导性之间的相互作用中起着支配作用:在线版本包含补充材料,可查阅 10.1007/s44214-024-00058-0。
{"title":"<ArticleTitle xmlns:ns0=\"http://www.w3.org/1998/Math/MathML\">The origin of the large <ns0:math><ns0:msub><ns0:mi>T</ns0:mi> <ns0:mi>c</ns0:mi></ns0:msub> </ns0:math> variation in FeSe thin films probed by dual-beam pulsed laser deposition.","authors":"Zhongpei Feng, Hua Zhang, Jie Yuan, Xingyu Jiang, Xianxin Wu, Zhanyi Zhao, Qiuhao Xu, Valentin Stanev, Qinghua Zhang, Huaixin Yang, Lin Gu, Sheng Meng, Suming Weng, Qihong Chen, Ichiro Takeuchi, Kui Jin, Zhongxian Zhao","doi":"10.1007/s44214-024-00058-0","DOIUrl":"10.1007/s44214-024-00058-0","url":null,"abstract":"<p><p>FeSe is one of the most enigmatic superconductors. Among the family of iron-based compounds, it has the simplest chemical makeup and structure, and yet it displays superconducting transition temperature ( <math><msub><mi>T</mi> <mtext>c</mtext></msub> </math> ) spanning 0 to 15 K for thin films, while it is typically 8 K for single crystals. This large variation of <math><msub><mi>T</mi> <mtext>c</mtext></msub> </math> within one family underscores a key challenge associated with understanding superconductivity in iron chalcogenides. Here, using a dual-beam pulsed laser deposition (PLD) approach, we have fabricated a unique lattice-constant gradient thin film of FeSe which has revealed a clear relationship between the atomic structure and the superconducting transition temperature for the first time. The dual-beam PLD that generates laser fluence gradient inside the plasma plume has resulted in a continuous variation in distribution of edge dislocations within a single film, and a precise correlation between the lattice constant and <math><msub><mi>T</mi> <mtext>c</mtext></msub> </math> has been observed here, namely, <math><msub><mi>T</mi> <mtext>c</mtext></msub> <mo>∝</mo> <msqrt><mrow><mi>c</mi> <mo>-</mo> <msub><mi>c</mi> <mn>0</mn></msub> </mrow> </msqrt> </math> , where <i>c</i> is the <i>c</i>-axis lattice constant (and <math><msub><mi>c</mi> <mn>0</mn></msub> </math> is a constant). This explicit relation in conjunction with a theoretical investigation indicates that it is the shifting of the <math><msub><mi>d</mi> <mtext>xy</mtext></msub> </math> orbital of Fe which plays a governing role in the interplay between nematicity and superconductivity in FeSe.</p><p><strong>Supplementary information: </strong>The online version contains supplementary material available at 10.1007/s44214-024-00058-0.</p>","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":"3 1","pages":"12"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11161545/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141297511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-10DOI: 10.1007/s44214-023-00038-w
Desheng Wu, Jianlin Luo
Abstract We reported herein the single crystal growth and the comprehensive study of basic physical properties including electronic transport, magnetic, specific heat of topological insulator candidate LaP. Single crystal LaP of rock salt type structure was synthesized by Sn flux method. Under low temperature and high magnetic field of $T= 2$ T=2 K and $B= 9$ B=9 T, large positive magnetoresistance (LMR) of 500% was discovered. The Hall effect measurements show that the conduction carriers are dominated by holes among the temperature range from 300 K to 2 K, the carrier concentration $n_{h} =4.94times 10^{19}$ nh=4.94×1019 cm −3 and $n_{e} =5.02times 10^{16}$ ne=5.02×1016 cm −3 and the mobility of LaP reached as high as $mu _{h}=1.57times 10^{4}$ μh=1.57×104 cm 2 V −1 S −1 and $mu _{e} = 1.55times 10^{3}$ μe=1.55×103 cm 2 V −1 S −1 obtained at 2 K, which can be explained by multiband model physics like other topological quantum material systems with large MR. LaP shows diamagnetism over a wide temperature range from 2 K to 300 K without any magnetic phase transition by susceptibility measurements. No evidence of phase transitions from 2 K to 300 K was observed in the specific heat measurement. The electronic specific heat coefficient is obtained 0.538 m J mol −1 K −2 for LaP single crystal, which responds to a small electron density state near the Fermi level. Our results would be helpful in renewing interest in studying emergent phenomena arisen from topological semimetals. LaP offers a platform for understanding the interactions between large magnetoresistance, high mobility an
{"title":"Large positive magnetoresistance and high mobility in topological insulator candidate LaP","authors":"Desheng Wu, Jianlin Luo","doi":"10.1007/s44214-023-00038-w","DOIUrl":"https://doi.org/10.1007/s44214-023-00038-w","url":null,"abstract":"Abstract We reported herein the single crystal growth and the comprehensive study of basic physical properties including electronic transport, magnetic, specific heat of topological insulator candidate LaP. Single crystal LaP of rock salt type structure was synthesized by Sn flux method. Under low temperature and high magnetic field of $T= 2$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>T</mml:mi> <mml:mo>=</mml:mo> <mml:mn>2</mml:mn> </mml:math> K and $B= 9$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>B</mml:mi> <mml:mo>=</mml:mo> <mml:mn>9</mml:mn> </mml:math> T, large positive magnetoresistance (LMR) of 500% was discovered. The Hall effect measurements show that the conduction carriers are dominated by holes among the temperature range from 300 K to 2 K, the carrier concentration $n_{h} =4.94times 10^{19}$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>n</mml:mi> <mml:mi>h</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>4.94</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>19</mml:mn> </mml:mrow> </mml:msup> </mml:math> cm −3 and $n_{e} =5.02times 10^{16}$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>n</mml:mi> <mml:mi>e</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>5.02</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>16</mml:mn> </mml:mrow> </mml:msup> </mml:math> cm −3 and the mobility of LaP reached as high as $mu _{h}=1.57times 10^{4}$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>μ</mml:mi> <mml:mi>h</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.57</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> </mml:math> cm 2 V −1 S −1 and $mu _{e} = 1.55times 10^{3}$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>μ</mml:mi> <mml:mi>e</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.55</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:math> cm 2 V −1 S −1 obtained at 2 K, which can be explained by multiband model physics like other topological quantum material systems with large MR. LaP shows diamagnetism over a wide temperature range from 2 K to 300 K without any magnetic phase transition by susceptibility measurements. No evidence of phase transitions from 2 K to 300 K was observed in the specific heat measurement. The electronic specific heat coefficient is obtained 0.538 m J mol −1 K −2 for LaP single crystal, which responds to a small electron density state near the Fermi level. Our results would be helpful in renewing interest in studying emergent phenomena arisen from topological semimetals. LaP offers a platform for understanding the interactions between large magnetoresistance, high mobility an","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":"119 33","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135137158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Two-dimensional (2D) Cr (1+ δ ) Te 2 materials exhibit strong magnetic ordering and high Curie temperatures, making them attractive for various applications. It is crucial to achieve controllable synthesis for their successful integration into device technologies. In this study, we present the synthesis of phase-controllable 2D Cr (1+ δ ) Te 2 films on the Si (111) substrate via molecular beam epitaxy. The composition and phase transition of the as-grown Cr (1+ δ ) Te 2 films are characterized by using in-situ reflection high-energy electron diffraction, scanning tunneling microscopy, ex-situ X-ray photoelectron spectroscopy, X-ray diffraction, and theoretical calculations. At low growth temperatures, by carefully adjusting the film thickness from 2 to more than 3 layers, we achieve precise control over the phase of Cr (1+ δ ) Te 2 , from CrTe 2 to Cr intercalated Cr 2 Te 3 . At a relatively elevated growth temperature, it is demonstrated that the Cr (1+ δ ) Te 2 phase is independent of the film thickness, only Cr 2 Te 3 forms and its growth mode is thickness-dependent. These phase transitions at low growth temperatures and growth mode changes at elevated growth temperatures are attributed to interfacial effects and the phase stability of Cr (1+ δ ) Te 2 compounds. Additionally, we utilize scanning tunneling spectroscopy and computations to gain insights into the electronic properties of Cr 2 Te 3 . The magnetic measurements reveal that the 30-nm Cr 2 Te 3 film exhibits ferromagnetic behavior with a Curie temperature of about 180 K. Our work offers a robust method for the controllable growth of high-quality 2D Cr (1+ δ ) Te 2 films on Si substrates, providing an ideal platform for investigating their intrinsic properties and advancing the development of 2D magnet-based spintronics devices.
二维(2D) Cr (1+ δ) Te 2材料具有强磁有序性和高居里温度,使其在各种应用中具有吸引力。实现可控合成是将其成功集成到器件技术中的关键。在本研究中,我们采用分子束外延的方法在Si(111)衬底上合成了相位可控的二维Cr (1+ δ) Te 2薄膜。采用原位反射高能电子衍射、扫描隧道显微镜、非原位x射线光电子能谱、x射线衍射和理论计算等方法对生长Cr (1+ δ) Te 2薄膜的组成和相变进行了表征。在低生长温度下,通过仔细调整薄膜厚度从2层到3层以上,我们实现了对Cr (1+ δ) Te 2的相的精确控制,从CrTe 2到Cr嵌入的cr2te 3。在较高的生长温度下,Cr (1+ δ) Te 2相与薄膜厚度无关,仅形成cr2te 3相,且其生长模式与薄膜厚度有关。这些低生长温度下的相变和高生长温度下的生长模式变化归因于界面效应和Cr (1+ δ) Te 2化合物的相稳定性。此外,我们利用扫描隧道光谱和计算来深入了解cr2te 3的电子性质。磁性测量结果表明,在居里温度为180k左右的情况下,30nm的cr2te - 3薄膜具有铁磁性。我们的工作为在Si衬底上可控地生长高质量的2D Cr (1+ δ) Te 2薄膜提供了一种稳健的方法,为研究其内在特性和推进二维磁性自旋电子学器件的发展提供了理想的平台。
{"title":"Controllable phase transition of two-dimensional ferromagnetic chromium telluride thin films grown by molecular beam epitaxy","authors":"Haili Huang, Jinbo Shen, Jiayi Chen, Qia Shen, Gaoting Lin, Zhen Zhu, Jiangtao Wu, Jie Ma, Hao Yang, Xiaoxue Liu, Liang Liu, Dandan Guan, Shiyong Wang, Yaoyi Li, Canhua Liu, Hao Zheng, Yunhao Lu, Jinfeng Jia","doi":"10.1007/s44214-023-00037-x","DOIUrl":"https://doi.org/10.1007/s44214-023-00037-x","url":null,"abstract":"Abstract Two-dimensional (2D) Cr (1+ δ ) Te 2 materials exhibit strong magnetic ordering and high Curie temperatures, making them attractive for various applications. It is crucial to achieve controllable synthesis for their successful integration into device technologies. In this study, we present the synthesis of phase-controllable 2D Cr (1+ δ ) Te 2 films on the Si (111) substrate via molecular beam epitaxy. The composition and phase transition of the as-grown Cr (1+ δ ) Te 2 films are characterized by using in-situ reflection high-energy electron diffraction, scanning tunneling microscopy, ex-situ X-ray photoelectron spectroscopy, X-ray diffraction, and theoretical calculations. At low growth temperatures, by carefully adjusting the film thickness from 2 to more than 3 layers, we achieve precise control over the phase of Cr (1+ δ ) Te 2 , from CrTe 2 to Cr intercalated Cr 2 Te 3 . At a relatively elevated growth temperature, it is demonstrated that the Cr (1+ δ ) Te 2 phase is independent of the film thickness, only Cr 2 Te 3 forms and its growth mode is thickness-dependent. These phase transitions at low growth temperatures and growth mode changes at elevated growth temperatures are attributed to interfacial effects and the phase stability of Cr (1+ δ ) Te 2 compounds. Additionally, we utilize scanning tunneling spectroscopy and computations to gain insights into the electronic properties of Cr 2 Te 3 . The magnetic measurements reveal that the 30-nm Cr 2 Te 3 film exhibits ferromagnetic behavior with a Curie temperature of about 180 K. Our work offers a robust method for the controllable growth of high-quality 2D Cr (1+ δ ) Te 2 films on Si substrates, providing an ideal platform for investigating their intrinsic properties and advancing the development of 2D magnet-based spintronics devices.","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":"176 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135321432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-17DOI: 10.1007/s44214-023-00035-z
Pinyuan Wang, Xiaoqi Liu, Jun Ge, Chen Ji, Haoran Ji, Yanzhao Liu, Yiwen Ai, Gaoxing Ma, S. Qi, Jian Wang
{"title":"Ferromagnetic and insulating behavior in both half magnetic levitation and non-levitation LK-99 like samples","authors":"Pinyuan Wang, Xiaoqi Liu, Jun Ge, Chen Ji, Haoran Ji, Yanzhao Liu, Yiwen Ai, Gaoxing Ma, S. Qi, Jian Wang","doi":"10.1007/s44214-023-00035-z","DOIUrl":"https://doi.org/10.1007/s44214-023-00035-z","url":null,"abstract":"","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45600219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-11DOI: 10.1007/s44214-023-00032-2
Zheshen Gao, Xue-Jian Gao, Wen-Yu He, Xiao Yan Xu, T. Ng, K. T. Law
{"title":"Correction: Topological superconductivity in multifold fermion metals","authors":"Zheshen Gao, Xue-Jian Gao, Wen-Yu He, Xiao Yan Xu, T. Ng, K. T. Law","doi":"10.1007/s44214-023-00032-2","DOIUrl":"https://doi.org/10.1007/s44214-023-00032-2","url":null,"abstract":"","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42598906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-15DOI: 10.1007/s44214-023-00029-x
H. Pi, Shuai Zhang, H. Weng
{"title":"Magnetic bulk photovoltaic effect as a probe of magnetic structures of $mathrm{{EuSn_{2}As_{2}}}$","authors":"H. Pi, Shuai Zhang, H. Weng","doi":"10.1007/s44214-023-00029-x","DOIUrl":"https://doi.org/10.1007/s44214-023-00029-x","url":null,"abstract":"","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46567867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-12DOI: 10.1007/s44214-023-00031-3
Yuantao Ji, Zehao Dong, Hao Wang, Qingyang Li, S. Ye, Zhi-En Gao, Zhenqi Hao, Yayu Wang
{"title":"Magnetic field orientation dependence of planar tunneling spectroscopy in the superconducting state of NbSe2","authors":"Yuantao Ji, Zehao Dong, Hao Wang, Qingyang Li, S. Ye, Zhi-En Gao, Zhenqi Hao, Yayu Wang","doi":"10.1007/s44214-023-00031-3","DOIUrl":"https://doi.org/10.1007/s44214-023-00031-3","url":null,"abstract":"","PeriodicalId":74629,"journal":{"name":"Quantum frontiers","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42676610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}