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Mott Gap Filling by Doping Electrons through Depositing One Sub-Monolayer Thin Film of Rb on Ca_(2)CuO_(2)Cl_(2)

Chinese Physics Letters 2024年第5期41卷 90-96页

作者：李寒王朝晖范圣泰李华州杨欢闻海虎 National Laboratory of Solid State Microstructures and Department of Physics Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Understanding the doping evolution from a Mott insulator to a superconductor probably holds the key to resolve the mystery of unconventional superconductivity in copper oxides. To elucidate the evolution of the electronic state starting from the Mott insulator, we dose the surface of the parent phase Ca_(2)CuO_(2)Cl_(2) by depositing Rb atoms, which are supposed to donate electrons to the CuO_(2) planes underneath. We successfully achieved the Rb sub-monolayer thin films in forming the square lattice. The scanning tunneling microscopy or spectroscopy measurements on the surface show that the Fermi energy is pinned within the Mott gap but close to the edge of the charge transfer band. In addition, an in-gap state appears at the bottom of the upper Hubbard band(UHB), and the Mott gap will be significantly diminished. Combined with the Cl defect and the Rb adatom/cluster results, the electron doping is likely to increase the spectra weight of the UHB for the double occupancy. Our results provide information to understand the electron doping to the parent compound of cuprates.

关键词： doping holds Electron

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Supercoiled DNA Minicircles under Double-strand Breaks

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Chinese Journal of Polymer Science 2024年第9期42卷 1353-1359,I0007页

作者： Ye-Peng Qiao Chun-Lai Ren National Laboratory of Solid State Microstructures and Department of Physics Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210093China

Understanding how supercoiled DNA releases intramolecular stress is essential for its functional ***,the molecular mechanism underlying the relaxation process remains insufficiently *** we employed MD simulations based on the oxDNA2 model to investigate the relaxation process of a 336-base pair supercoiled minicircular DNA under double-strand breaks with two fixed *** simulations show that the conformational changes in the DNA occur continuously,with intramolecular stress release happening abruptly only when the DNA chain traverses the breakage *** relaxation process is influenced not only by the separation distance between the fixed ends but also their ***,we observe an inhibitory effect on the relaxation characterized by small angles,where short terminal loops impede DNA conformational adjustments,preserving the supercoiled *** findings elucidate the intricate interplay between DNA conformational change,DNA motion and intramolecular stress release,shedding light on the mechanisms governing the relaxation of supercoiled DNA at the molecular level.

关键词： Supercoiled DNA DNA minicircle DNA relaxation oxDNA model MD simulation

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Fabrication of two-dimensional van der Waals moiré superlattices

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Chinese Physics B 2025年第4期34卷 12-27页

作者： Zihao Wan Chao Wang Hang Zheng Wenna Tang Zihao Fu Weilin Liu Zhenjia Zhou Jun Li Guowen Yuan Libo Gao National Laboratory of Solid State Microstructures Jiangsu Key Laboratory for NanotechnologySchool of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Two-dimensional(2D)van der Waals(vdW)moiré superlattices have attracted significant attention due to their novel physical properties and quantum *** realization of these fascinating properties,however heavily depends on the quality of the measured moiré superlattices,emphasizing the importance of advanced fabrication *** review provides an in-depth discussion of the methods for fabricating moiré *** begins with a brief overview of the structure,properties,and potential applications of moiré superlattices,followed by a detailed examination of fabrication techniques,focuses on different kinds of transfer techniques and growth methods,particularly chemical vapor deposition(CVD)***,it addresses current challenges in fabricating high-quality moiré superlattices and discusses potential directions for future advancements in this *** review will enhance the understanding of moiré superlattice fabrication and contributing to the continued development of 2D twistronics.

关键词： 2D materials moirésuperlattices fabrication techniques chemical vapor deposition(CVD)

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Direct measurement of nonlocal quantum states without approximation

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Chinese Physics B 2023年第11期32卷 252-256页

作者：杨冈杨然龚彦晓祝世宁 National Laboratory of Solid State Microstructure School of Physics and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Efficient acquiring information from a quantum state is important for research in fundamental quantum physics and quantum information applications. Instead of using standard quantum state tomography method with reconstruction algorithm, weak values were proposed to directly measure density matrix elements of quantum state. Recently, similar to the concept of weak value, modular values were introduced to extend the direct measurement scheme to nonlocal quantum wavefunction. However, this method still involves approximations, which leads to inherent low precision. Here, we propose a new scheme which enables direct measurement for ideal value of the nonlocal density matrix element without taking approximations. Our scheme allows more accurate characterization of nonlocal quantum states, and therefore has greater advantages in practical measurement scenarios.

关键词： direct measurement quantum tomography nonlocal quantum state

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MAGUS: machine learning and graph theory assisted universal structure searcher

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National Science Review 2023年第7期10卷 213-233页

作者： Junjie Wang Hao Gao Yu Han Chi Ding Shuning Pan Yong Wang Qiuhan Jia Hui-Tian Wang Dingyu Xing Jian Sun National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Advanced Microstructures Nanjing University

Crystal structure predictions based on first-principles calculations have gained great success in materials science and solid state ***,the remaining challenges still limit their applications in systems with a large number of atoms,especially the complexity of conformational space and the cost of local optimizations for big ***,we introduce a crystal structure prediction method,MAGUS,based on the evolutionary algorithm,which addresses the above challenges with machine learning and graph *** used in the program are summarized in detail and benchmark tests are *** intensive tests,we demonstrate that on-the-fly machine-learning potentials can be used to significantly reduce the number of expensive first-principles calculations,and the crystal decomposition based on graph theory can efficiently decrease the required configurations in order to find the target *** also summarized the representative applications of this method on several research topics,including unexpected compounds in the interior of planets and their exotic states at high pressure and high temperature(superionic,plastic,partially diffusive state,etc.);new functional materials(superhard,high-energy-density,superconducting,photoelectric materials),*** successful applications demonstrated that MAGUS code can help to accelerate the discovery of interesting materials and phenomena,as well as the significant value of crystal structure predictions in general.

关键词： crystal structure searching materials design ab-initio calculations density functional theory high-pressure phase transition

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Signature of Superconductivity in Pressurized La_(4)Ni_(3)O_(10)

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Chinese Physics Letters 2024年第1期41卷 77-84页

作者：李庆张英杰项浙宁张宇航祝熙宇闻海虎 National Laboratory of Solid State Microstructures and Department of Physics Center for Superconducting Physics and MaterialsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

The discovery of high-temperature superconductivity near 80K in bilayer nickelate La_(3)Ni_(2)O_(7)under high pressures has renewed the exploration of superconducting nickelate in bulk *** extension of superconductivity in other nickelates in a broader family is also ***,we report the experimental observation of superconducting signature in trilayer nickelate La_(4)Ni_(3)O_(10)under high *** using a modified solgel method and post-annealing treatment under high oxygen pressure,we successfully obtained polycrystalline La_(4)Ni_(3)O_(10)samples with different transport behaviors at ambient *** we performed high-pressure electrical resistance measurements on these samples in a diamond-anvil-cell ***,the signature of possible superconducting transition with a maximum transition temperature(T_(c))of about 20K under high pressures is observed,as evidenced by a clear drop of resistance and the suppression of resistance drops under magnetic *** the resistance drop is sample-dependent and relatively small,it appears in all of our measured *** argue that the observed superconducting signal is most likely to originate from the main phase of La_(4)Ni_(3)O_(10).Our findings will motivate the exploration of superconductivity in a broader family of nickelates and shed light on the understanding of the underlying mechanisms of high-T_(c) superconductivity in nickelates.

关键词： materials superconductivity signature

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Polarization structure transition of C-point singularities upon reflection

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Science China(Physics,Mechanics & Astronomy) 2025年第4期68卷 101-111页

作者： Weiming Zhen Zhi-Cheng Ren Xi-Lin Wang Jianping Ding Hui-Tian Wang National Laboratory of Solid State Microstructures and School of Physics Nanjing UniversityNanjing210093China Collaborative Innovation Center of Advanced Microstructures Nanjing210093China Collaborative Innovation Center of Solid-State Lighting and Energy-Saving Electronics Nanjing210093China

This paper provides a comprehensive study of the polarization transition of reflected C-point *** reflection of star-and lemon-type C-point paraxial vector beams at an air-dielectric interface is *** small oblique incidences,a topological phase transition is observed exclusively in spin-maintained modes,manifesting as a shift from a vortex phase to a spin ***,as the incident angle ranges from 0 to 90 degrees,another topological phase transition occurs,the total spin components of the reflected field undergoing an interchange of topological charges(TCs),resulting in a type transition of the C-point from the star(lemon)-type to the lemon(star)-***,the concurrence of the C-point beam throughout the reflection process can be modulated by the incident angle,spanning almost the entire spectrum from 0 to *** longitudinal and transverse displacements of each spin component as well as the overall beam shifts of the reflected beam are further analyzed,revealing their dependence on the incident beam's TC *** findings offer novel physical insights into polarization singularity-matter interactions,holding promise for advancing research in singular optics and its applications.

关键词： optical singularities optical vortices polarization reflection structured light

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Ferromagnetism and insulating behavior with a logarithmic temperature dependence of resistivity in Pb_(10-x)Cux(PO_(4))_(6)O

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 106-111页

作者： Yuhang Zhang Cong Liu Xiyu Zhu Hai-Hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Recent claim of discovering above-room-temperature superconductivity(Tc≈400 K)at ambient pressure in copper doped apatite Pb10(PO_(4))_(6)O has stimulated world-wide enthusiasm and impulse of motion.A lot of follow-up works have been carried out with controversial *** check whether superconductivity is really present or absent in the material,we need samples which should have a rather pure phase of Pb_(10-x)Cux(PO_(4))_(6)*** we report the characterization results from the Pb_(10-x)Cux(PO_(4))_(6)O with a fraction of about 97 wt.%inferred from the fitting to the X-ray diffraction pattern,if assuming Cu2S as the only *** resistivity measurements show that it is a semiconductor characterized roughly by a ln(1/T)temperature dependence in wide temperature region without trace of *** measurements show that it has a general ferromagnetic signal with a weak superparamagnetic *** grains of the sample show clear interactions with a Nb Fe B *** detected Cu concentration is much lower than the expected nominal *** results show the absence of metallicity and superconductivity in Pb_(10-x)Cux(PO_(4))_(6)O at ambient pressure,and suggest the presence of strong correlation effect.

关键词： superconductivity Pb10(PO4)6O ferromagnetic correlation effect

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Quantized bound states around a vortex in anisotropic superconductors

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 146-155页

作者： Ke Xiang Da Wang Qiang-Hua Wang National Laboratory of Solid State Microstructures&School of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

The bound states around a vortex in anisotropic superconductors is a longstanding yet important *** this work,we develop a variational theory on the basis of the Andreev approximation to obtain the energy levels and wave functions of the low-energy quantized bound states in superconductors with anisotropic pairing on arbitrary Fermi *** the case of circular Fermi surface,the effective Schr¨odinger equation yielding the bound state energies gets back to the theory proposed by Volovik and Kopnin many years *** generalization here enables us to prove the equidistant energy spectrum inside a vortex in a broader class of *** importantly,we are now able to obtain the wave functions of these bound states by projecting the quasiclassical wave function on the eigenmodes of the effective Schr¨odinger equation,going beyond the quasiclassical Eilenberger results,which,as we find,are sensitive to the scattering *** the case of isotropic Fermi surface,the spatial profile of the low-energy local density of states is dominated near the vortex center and elongates along the gap antinode directions,in addition to the ubiquitous Friedel oscillation arising from the quantum inteference neglected in the Eilenberger ***,as a consequence of the pairing anisotropy,the quantized wave functions develop a peculiar distribution of winding number,which reduces stepwise towards the vortex *** work provides a flexible way to study the vortex bound states in the future.

关键词： vortex bound state anisotropic superconductor Andreev approximation

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One-Dimensional Implantable Sensors for Accurately Monitoring Physiological and Biochemical Signals

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Research 2024年第4期2024卷 42-57页

作者： Qianming Li Wen Wang Haotian Yin Kuangyi Zou Yiding Jiao Ye Zhang National Laboratory of Solid State Microstructures Jiangsu Key Laboratory of Artificial Functional MaterialsChemistry and Biomedicine Innovation CenterCollaborative Innovation Center of Advanced MicrostructuresCollege of Engineering and Applied SciencesNanjing UniversityNanjing 210023China

In recent years,one-dimensional(1D)implantable sensors have received considerable attention and rapid development in the biomedical field due to their unique structural characteristics and high integration *** sensors can be implanted into the human body with minimal invasiveness,facilitating real-time and accurate monitoring of various physiological and pathological *** review examines the latest advancements in 1D implantable sensors,focusing on the material design of sensors,device integration,implantation methods,and the construction of the stable sensor–tissue ***,a comprehensive overview is provided regarding the applications and future research directions for 1D implantable sensors with an ultimate aim to promote their utilization in personalized healthcare and precision medicine.

关键词： integration implantation directions

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