{"title":"Deep learning in two-dimensional materials: Characterization, prediction, and design","authors":"Xinqin Meng, Chengbing Qin, Xilong Liang, Guofeng Zhang, Ruiyun Chen, Jianyong Hu, Zhichun Yang, Jianzhong Huo, Liantuan Xiao, Suotang Jia","doi":"10.1007/s11467-024-1394-7","DOIUrl":"10.1007/s11467-024-1394-7","url":null,"abstract":"<div><p>Since the isolation of graphene, two-dimensional (2D) materials have attracted increasing interest because of their excellent chemical and physical properties, as well as promising applications. Nonetheless, particular challenges persist in their further development, particularly in the effective identification of diverse 2D materials, the domains of large-scale and high-precision characterization, also intelligent function prediction and design. These issues are mainly solved by computational techniques, such as density function theory and molecular dynamic simulation, which require powerful computational resources and high time consumption. The booming deep learning methods in recent years offer innovative insights and tools to address these challenges. This review comprehensively outlines the current progress of deep learning within the realm of 2D materials. Firstly, we will briefly introduce the basic concepts of deep learning and commonly used architectures, including convolutional neural and generative adversarial networks, as well as U-net models. Then, the characterization of 2D materials by deep learning methods will be discussed, including defects and materials identification, as well as automatic thickness characterization. Thirdly, the research progress for predicting the unique properties of 2D materials, involving electronic, mechanical, and thermodynamic features, will be evaluated succinctly. Lately, the current works on the inverse design of functional 2D materials will be presented. At last, we will look forward to the application prospects and opportunities of deep learning in other aspects of 2D materials. This review may offer some guidance to boost the understanding and employing novel 2D materials.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11467-024-1394-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zidong Lin, Hongfeng Liu, Kai Tang, Yidai Liu, Liangyu Che, Xinyue Long, Xiangyu Wang, Yu-ang Fan, Keyi Huang, Xiaodong Yang, Tao Xin, Xinfang Nie, Dawei Lu
{"title":"Hardware-efficient quantum principal component analysis for medical image recognition","authors":"Zidong Lin, Hongfeng Liu, Kai Tang, Yidai Liu, Liangyu Che, Xinyue Long, Xiangyu Wang, Yu-ang Fan, Keyi Huang, Xiaodong Yang, Tao Xin, Xinfang Nie, Dawei Lu","doi":"10.1007/s11467-024-1391-x","DOIUrl":"10.1007/s11467-024-1391-x","url":null,"abstract":"<div><p>Principal component analysis (PCA) is a widely used tool in machine learning algorithms, but it can be computationally expensive. In 2014, Lloyd, Mohseni & Rebentrost proposed a quantum PCA (qPCA) algorithm [<i>Nat. Phys.</i> 10, 631 (2014)] that has not yet been experimentally demonstrated due to challenges in preparing multiple quantum state copies and implementing quantum phase estimations. In this study, we presented a hardware-efficient approach for qPCA, utilizing an iterative approach that effectively resets the relevant qubits in a nuclear magnetic resonance (NMR) quantum processor. Additionally, we introduced a quantum scattering circuit that efficiently determines the eigenvalues and eigenvectors (principal components). As an important application of PCA, we focused on classifying thoracic CT images from COVID-19 patients and achieved high accuracy in image classification using the qPCA circuit implemented on the NMR system. Our experiment highlights the potential of near-term quantum devices to accelerate qPCA, opening up new avenues for practical applications of quantum machine learning algorithms.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peng Zhao, Wei Zhong, Ming-Ming Du, Xi-Yun Li, Lan Zhou, Yu-Bo Sheng
{"title":"Quantum secure direct communication with hybrid entanglement","authors":"Peng Zhao, Wei Zhong, Ming-Ming Du, Xi-Yun Li, Lan Zhou, Yu-Bo Sheng","doi":"10.1007/s11467-024-1396-5","DOIUrl":"10.1007/s11467-024-1396-5","url":null,"abstract":"<div><p>Quantum secure direct communication (QSDC) can transmit secret messages without keys, making it an important branch of quantum communication. We present a hybrid entanglement-based quantum secure direct communication (HE-QSDC) protocol with simple linear optical elements, combining the benefits of both continuous variables (CV) and discrete variables (DV) encoding. We analyze the security and find that the QSDC protocol has a positive security capacity when the bit error rate is less than 0.073. Compared with previous DV QSDC protocols, our protocol has higher communication efficiency due to performing nearly deterministic Bell-state measurement. On the other hand, compared with CV QSDC protocol, this protocol has higher fidelity with large α. Based on these advantages, our protocol may provide an alternative approach to realize secure communication.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tingting Fan, Cuihong Wen, Jiliang Jing, Jieci Wang
{"title":"Genuine tripartite entanglement and geometric quantum discord in entangled three-body Unruh–DeWitt detector system","authors":"Tingting Fan, Cuihong Wen, Jiliang Jing, Jieci Wang","doi":"10.1007/s11467-024-1398-3","DOIUrl":"10.1007/s11467-024-1398-3","url":null,"abstract":"<div><p>We studied the quantum correlations of a three-body Unruh–DeWitt detector system using genuine tripartite entanglement (GTE) and geometric quantum discord (GQD). We considered two representative three-body initial entangled states, namely the GHZ state and the W state. We demonstrated that the quantum correlations of the tripartite system are completely destroyed at the limit of infinite acceleration. In particular, it is found that the GQD of the two initial states exhibits “sudden change” behavior with increasing acceleration. It is shown that the quantum correlations of the W state are more sensitive than those of the GHZ state under the effect of Unruh thermal noise. The GQD is a more robust quantum resource than the GTE, and we can achieve robustness in discord-type quantum correlations by selecting the smaller energy gap in the detector. These findings provide guidance for selecting appropriate quantum states and resources for quantum information processing tasks in a relativistic setting.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-mobility spin-polarized two-dimensional electron gas at the interface of LaTiO3/SrTiO3 (110) heterostructures","authors":"Zhao-Cai Wang, Zheng-Nan Li, Shuang-Shuang Li, Weiyao Zhao, Ren-Kui Zheng","doi":"10.1007/s11467-024-1395-6","DOIUrl":"10.1007/s11467-024-1395-6","url":null,"abstract":"<div><p>High-quality antiferromagnetic Mott insulator thin films of LaTiO<sub>3</sub> (LTO) were epitaxially grown onto SrTiO<sub>3</sub> (STO) (110) substrates using the pulsed laser deposition. The LTO/STO heterostructures are not only highly conducting and ferromagnetic, but also show Kondo effect, Shubnikov-de Haas (SdH) oscillations with a nonzero Berry phase of <i>π</i>, and low-field hysteretic negative magnetoresistance (MR). Angle-dependent SdH oscillations and a calculation of the thickness of the interfacial conducting layer indicate the formation of a 4-nm high mobility two-dimensional electron gas (2DEG) layer at the interface. Moreover, an amazingly large low-field negative MR of ∼61.8% is observed at 1.8 K and 200 Oe, which is approximately one to two orders of magnitude larger than those observed in other spin-polarized 2DEG oxide systems. All these results demonstrate that the 2DEG is spin-polarized and the 4-nm interfacial layer is ferromagnetic, which are attributed to the presence of magnetic Ti<sup>3+</sup> ions due to interfacial oxygen vacancies and the diffusion of La<sup>3+</sup> ions into the STO substrate. The localized Ti<sup>3+</sup> magnetic moments couple to high mobility itinerant electrons under magnetic fields, giving rise to the observed low-field MR. Our work demonstrates the great potential of antiferromagnetic titanate oxide interface for designing spin-polarized 2DEG and spintronic devices.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A spin–rotation mechanism of Einstein–de Haas effect based on a ferromagnetic disk","authors":"Xin Nie, Jun Li, Trinanjan Datta, Dao-Xin Yao","doi":"10.1007/s11467-023-1389-9","DOIUrl":"10.1007/s11467-023-1389-9","url":null,"abstract":"<div><p>Spin–rotation coupling (SRC) is a fundamental interaction that connects electronic spins with the rotational motion of a medium. We elucidate the Einstein–de Haas (EdH) effect and its inverse with SRC as the microscopic mechanism using the dynamic spin–lattice equations derived by elasticity theory and Lagrangian formalism. By applying the coupling equations to an iron disk in a magnetic field, we exhibit the transfer of angular momentum and energy between spins and lattice, with or without damping. The timescale of the angular momentum transfer from spins to the entire lattice is estimated by our theory to be on the order of 0.01 ns, for the disk with a radius of 100 nm. Moreover, we discover a linear relationship between the magnetic field strength and the rotation frequency, which is also enhanced by a higher ratio of Young’s modulus to Poisson’s coefficient. In the presence of damping, we notice that the spin-lattice relaxation time is nearly inversely proportional to the magnetic field. Our explorations will contribute to a better understanding of the EdH effect and provide valuable insights for magneto-mechanical manufacturing.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jingxuan Sun, Yachen Wang, Congyu Zhang, Lijun Xu, Bo Fu
{"title":"Spatiotemporal nonlinear dynamics in multimode fiber laser based on carbon nanotubes","authors":"Jingxuan Sun, Yachen Wang, Congyu Zhang, Lijun Xu, Bo Fu","doi":"10.1007/s11467-024-1399-2","DOIUrl":"10.1007/s11467-024-1399-2","url":null,"abstract":"<div><p>We investigated 1-µm multimode fiber laser based on carbon nanotubes, where multiple typical pulse states were observed, including Q-switched, Q-switched mode-locked, and spatiotemporal mode-locked pulses. Particularly, stable spatiotemporal mode-locking was realized with a low threshold, where the pulse duration was 37 ps and the wavelength was centred at 1060.5 nm. Moreover, both the high signal to noise and long-term operation stability proved the reliability of the mode-locked laser. Furthermore, the evolution of the spatiotemporal mode-locked pulses in the cavity was also simulated and discussed. This work exhibits the flexible outputs of spatiotemporal phenomena in multimode lasers based on nanomaterials, providing more possibilities for the development of high-dimensional nonlinear dynamics.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sub-5 nm bilayer GaSe MOSFETs towards ultrahigh on-state current","authors":"Xueping Li, Xiaojie Tang, Zhuojun Wang, Peize Yuan, Lin Li, Chenhai Shen, Congxin Xia","doi":"10.1007/s11467-023-1390-3","DOIUrl":"10.1007/s11467-023-1390-3","url":null,"abstract":"<div><p>Dielectric engineering plays a crucial role in the process of device miniaturization. Herein we investigate the electrical properties of bilayer GaSe metal-oxide-semiconductor field-effect transistors (MOSFETs), considering hetero-gate-dielectric construction, dielectric materials and GaSe stacking pattern. The results show that device performance strongly depends on the dielectric constants and locations of insulators. When high-<i>k</i> dielectric is placed close to the drain, it behaves with a larger on-state current (<i>I</i><sub>on</sub>) of 5052 µA/µm when the channel is 5 nm. Additionally, when the channel is 5 nm and insulator is HfO<sub>2</sub>, the largest <i>I</i><sub>on</sub> is 5134 µA/µm for devices with AC stacking GaSe channel. In particular, when the gate length is 2 nm, it still meets the HP requirements of ITRS 2028 for the device with AA stacking when high-<i>k</i> dielectric is used. Hence, the work provides guidance to regulate the performance of the two-dimensional nanodevices by dielectric engineering.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 5","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A universal non-Hermitian platform for bound state in the continuum enhanced wireless power transfer","authors":"Haiyan Zhang, Zhiwei Guo, Yunhui Li, Yaping Yang, Yuguang Chen, Hong Chen","doi":"10.1007/s11467-023-1388-x","DOIUrl":"10.1007/s11467-023-1388-x","url":null,"abstract":"<div><p>Non-Hermitian systems with parity–time (PT)-symmetry have been extensively studied and rapidly developed in resonance wireless power transfer (WPT). The WPT system that satisfies PT-symmetry always has real eigenvalues, which promote efficient energy transfer. However, meeting the condition of PT-symmetry is one of the most puzzling issues. Stable power transfer under different transmission conditions is also a great challenge. Bound state in the continuum (BIC) supporting extreme quality-factor mode provides an opportunity for efficient WPT. Here, we propose theoretically and demonstrate experimentally that BIC widely exists in resonance-coupled systems without PT-symmetry, and it can even realize more stable and efficient power transfer than PT-symmetric systems. Importantly, BIC for efficient WPT is universal and suitable in standard second-order and even high-order WPT systems. Our results not only extend non-Hermitian physics beyond PT-symmetry, but also bridge the gap between BIC and practical application engineering, such as highperformance WPT, wireless sensing and communications.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 4","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bocheng Lei (, ), Aolin Li (, ), Wenzhe Zhou (, ), Yunpeng Wang (, ), Wei Xiong (, ), Yu Chen (, ), Fangping Ouyang (, )
{"title":"Room-temperature ferromagnetism and half-metallicity in monolayer orthorhombic CrS2","authors":"Bocheng Lei \u0000 (, ), Aolin Li \u0000 (, ), Wenzhe Zhou \u0000 (, ), Yunpeng Wang \u0000 (, ), Wei Xiong \u0000 (, ), Yu Chen \u0000 (, ), Fangping Ouyang \u0000 (, )","doi":"10.1007/s11467-023-1387-y","DOIUrl":"10.1007/s11467-023-1387-y","url":null,"abstract":"<div><p>Two-dimensional materials with high-temperature ferromagnetism and half-metallicity have the latest applications in spintronic devices. Based on first-principles calculations, we have investigated a novel two-dimensional CrS<sub>2</sub> phase with an orthorhombic lattice. Our results suggest that it is stable in dynamics, thermodynamics, and mechanics. The ground state of monolayer orthorhombic CrS<sub>2</sub> is both ferromagnetic and half-metallic, with a high Curie temperature of 895 K and a large spin-flipping gap on values of 0.804 eV. This room-temperature ferromagnetism and half-metallicity can maintain stability against a strong biaxial strain ranging from −5% to 5%. Meanwhile, increasing strain can significantly maintain the out-of-plane magnetic anisotropy. A density of states analysis, together with the orbital-resolved magnetic anisotropy energy, has revealed that the strain-enhanced MAE is highly related to the 3d-orbital splitting of Cr atoms. Our results suggest the monolayer orthorhombic CrS<sub>2</sub> is an ideal candidate for future spintronics.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":"19 4","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}