锂离子电池与能源革命 | 本周物理学讲座

来源：中国物理学会期刊网

1锂离子电池与能源革命

报告人：黄学杰，中科院物理研究所

时间：10月16日（周三）10:00

单位：中科院物理研究所

地点：M234报告厅

2019年诺贝尔化学奖授予了John Goodenough、Stanley Whittingham和吉野彰，以表彰他们在锂离子电池开发方面所做的贡献。诞生于1970-80年代的锂离子电池今天正在深入推进一场能源领域的革命，“烧油开车、燃煤发电”的时代将在未来几十年内结束。本报告将重点介绍了锂离子电池及其关键材料早期发现历史、锂离子电池技术产业化历程、锂离子电池对能源革命的重要意义、当前锂离子电池技术的发展趋势、后锂离子电池时代的二次电池技术等。

2Interplay between CDW and superconducting fluctuations in high-Tc cuprates

报告人：Brigitte Leridon，Laboratoire de Physique et d'Etude des Matériaux

时间：10月15日（周二）10:00

单位：中科院物理研究所

地点：M236 会议室

The phase diagram of underdoped superconducting cuprates is known to be extremely rich and complex. In addition to a transition from an antiferromagnetic insulator at half-doping to a strange metal at optimal doping, and the opening of a pseudogap in the density of states, the normal state is also the location for a charge ordering and a Fermi surface reconstruction. By analyzing La1-xSrxCuO4 thin films resistivity under high pulsed magnetic field for various doping, I will carefully inspect the behavior of superconducting thermal and quantum fluctuations and the existence of quantum critical points. I will extract a systematic (H,T) phase diagram and discuss the interplay between charge ordering and superconductivity. In particular I will relate our findings to a theoretical model proposed by J. Lorenzana and A. Attanasi, which enables to demonstrate that disorder can induce a charge-density-wave to become superconducting. This paradoxical e?ect occurs close to the phase boundary between CDW and SC and is analogous to the occurrence of supersolid effects in 4He. It originates from the topological stabilization of filamentary superconductivity at the interfaces of different CDW domains at low temperature and intermediate/large magnetic fields. By comparing experimental and theoretical phase diagrams I will show that the previously observed two-step phase transition in under-doped films is related to the interplay between superconducting fluctuations and CDW. I will then analyze the doping dependence of this diagram and show that p=1/8 is specific for this CDW/SC competition at least in LSCO, since the coexistence takes place at zero magnetic field for this specific doping.

310dB vacuum noise squeezing and its application to the gravitational wave detector and on-chip quantum circuits

报告人：李瑞光，台湾清华大学

时间：10月15日（周二）10:00

单位：中科院物理研究所

地点：M253 会议室

 In this talk, I will report our recent implementation of squeezed vacuum states at 1064 nm. With a bow-tie, optical parametric oscillator cavity, and our home-made balanced homodyne detectors, noise reduction up to 10dB below the vacuum is measured. With the operation of a 300 m filter cavity prototype installed at the National Astronomical Observatory of Japan, application of such a vacuum squeezed state to the gravitational wave detector, in order to achieve a broadband reduction, will be discussed. At the same time, based on the niche of silicon photonics technologies and semiconductor industries in Taiwan, we will also introduce our new project toward the implementation of scalable quantum photonic chips by integrating photonic qubits, optical components based on silicon photonics, and photon detector arrays.

4 Challenge to the Black Hole Model of quasars and Active Galactic Nuclei

报告人：Qiuhe Peng (Nanjing U)

时间：10月15日（周二）12:00

单位：北京大学

地点：1st meeting room, KIAA

part I: On our Galactic Center: An unusually strong radial magnetic field has been found near our Galactic Center (Eatough  et al., 2013) Its important implication is that the observed radiation from the GC cannot be emitted by the gas of the accretion disk due to accretion plasma fluid being hard to  transfer  cross the magnetic field line by the Lorentz force. This is the first dilemma of the standard accretion disk model of black hole at the GC (Peng et al. 2016). The second dilemma is that the magnetic field with a lower limit of 8mG near the GC is  hardly produced by ɑ-turbulence dynamo mechanism (Peng et al. 2016). Then I would like talk that the strong radial magnetic field detected in the vicinity of the GC is consistent with the prediction from our model of supermassive object with magnetic monopoles ( Peng and Chou 2001). This is a strong evidence of both no black hole at the GC and existence of magnetic monopoles (Peng et al., 2016, 2017a). Taking the RC effect (nucleons may decay catalyzed by MM) as an energy source, besides, we have proposed an unified model for various supernova explosion(Peng et al. 2017b). In our model, the remnant of the collapsed core of supernova is still a neutron star rather than a black hole no matter how huge of the supernova mass. That means, black holes with stellar mass are impossible to be formed through supernova explosion. part II: Query on the black hole models for other quasars and active galactic nuclei: The key dilemma of the black hole model is the question on the BH mass at the center of AGNs . The radiation from the BHs is due to accreting the material of accretion disk around the BHs. According to the Mach principle, the mass distribution of the universe (different redshifts) of the black holes formed in the early universe (with the number of black holes formed) was roughly the same. Through the accretion process, the mass of black holes could only increase continuously. If we assume that all quasars were born at the same primordial era, then the detected (observed) accreted mass of the BH through accretion disk (by the current theories of the accretion disk) should be took off . Then the mass of BHs in the lower redshift region would be very small or negative . However, the dilemma will disappear in our model of Supper-massive Stars with magnetic monopoles ( Peng and Chou 2001).

5Constructing Polymorphic Nanodomains in BaTiO3 Films via Epitaxial Symmetry Engineering

报告人：彭威，首尔大学

时间：10月15日（周二）14:00

单位：北京师范大学

地点：科技楼A区311

Ferroelectric materials owning a polymorphic nanodomain structure usually exhibit colossal susceptibilities to external fields, thus holding huge potential for piezoelectric, dielectric, and thermoelectric devices. Despite the success of traditional strategies via complex composition engineering, alternative simple methods using such as strain and electric fields have been intensively searched to achieve the polymorphic nanodomain state in lead-free, simple-composition oxide ferroelectrics in recent years. Here, a nanodomain structure with morphed structural phases is realized in an epitaxial BaTiO3 film grown on a (111)-oriented SrTiO3 substrate. Using a combination of experimental and theoretical approaches, it is revealed that a three-fold rotational symmetry element enforced by the epitaxial constraint along the [111] direction in BaTiO3 introduces significant instability among intrinsic tetragonal, orthorhombic, and rhombohedral phases. Such a phase degeneracy induces dense ferroelectric nanodomains (1-10 nanometers) with low-angle domain walls, which significantly enhances dielectric and piezoelectric properties. Therefore, this finding signifies the important role of epitaxial symmetry in domain engineering of oxide ferroelectrics, and further the development of functional devices.

6内涵都在表面上

报告人：曹则贤，中科院物理研究所

时间：10月18日（周五）18:30

单位：中国科学院大学

地点：雁栖湖校区教1-009

空间是三维的，则有限存在物对它者所呈现的只能是在一个二维表面上。维度更多的空间中，表面会具有更大的重要性。表面是物体展现各种性质的窗口，是物体间相互作用的舞台。幸运的是，很多情形下表面能反映一个体系的全部内涵，相应的数学表达就隐藏在物理公式中。表面科学是凝聚态的重要分支，材料应用因表面和层状结构的创新设计而精彩纷呈。

7片上集成硅基光源

报告人：骆军委，中国科学院半导体研究所

时间：10月16日（周三）15:10

单位：北京大学

地点：物理楼中楼212教室

光子器件与电子器件集成在同一硅片上的光电子集成技术可以有效解决微电子芯片所面临的诸多难题延续摩尔定律。目前，在硅片上已经研制成功探测器、波导、调制器等光子组件，由于硅不发光导致硅片上的激光器还无法成功，严重阻碍了光电集成技术的发展。硅发光是一个延续了半个世纪的世界难题。我们最近发展了一个普适理论来统一解释为什么硅、锗、金刚石等IV 族是间接带隙，而所有II-VI族半导体是直接带隙，除含铝化合物和GaP外的其他III-V族半导体都是直接带隙，解释清楚了为什么过去半个多世纪始终无法解决硅基发光的难题。我们推翻了硅量子点国际权威荷兰阿姆斯特丹大学Tom Gregorkiewicz教授认为硅量子点可以实现间接带隙转变为直接带隙的观点，Tom Gregorkiewicz教授发现随硅量子点减小直接带隙能量迅速降低，认为硅量子点足够小可以成为真正的直接带隙，这给硅量子点发光带来了新的希望。我们的研究否定了硅量子点发光的可行性。我们也设计出了高效发光硅锗复杂超晶格，把文献报道的硅锗超晶格最高发光效率提高了50倍，达到通信激光器材料直接带隙体InP的10%。最近，考虑到锗的直接带隙只比间接带隙高0.14 eV，只需要2%的张应变就能使锗完成间接带隙到直接带隙的转变实现高效发光，受到锂电池硅锗阳极材料体积最大可以膨胀400%的启发，提出往锗中注入锂或惰性气体原子，等使锗体积膨胀实现直接带隙发光的原创方案，该掺杂应变锗直接带隙发光方案高度兼容CMOS工艺，如果可行将解决微电子芯片上的光源问题，极大推动光电集成技术的发展。

8基于功能氧化物外延膜的类脑器件

报告人：葛琛，中科院物理所

时间：10月17日（周四）10:00

单位：北京师范大学

地点：物理楼106

类似于人脑的神经网络型信息处理模式效率将会明显优于传统架构计算机，开发符合神经形态计算特性的电子器件（电子突触）从而构建大规模人工神经网络，最终实现人工智能产业亟需的高性能低功耗“类脑芯片”，已经成为未来信息科技发展的一个重要方向。近期，我们在基于功能氧化物外延膜的新型电解质突触晶体管方向取得系列进展，侧重于在高质量功能氧化物外延薄膜中阐明器件物理。我们通过激光分子束外延技术制备高质量WO3外延薄膜，实现高性能神经突触晶体管器件。并系统研究极化离子液体调控WO3相变的物理机制：当门电压小于水的分解电位时离子液体调控主要是静电场效应起作用，撤掉门电压沟道电导立刻恢复，可以模拟突触的短程记忆过程；当门电压小于水的分解电位时离子液体调控主要是电化学效应起作用，伴随着H+在WO3薄膜A位空隙的插入，对应着长程记忆过程。我们不仅可以利用极化离子液体调控H+还可以调控O2-在钙钛矿材料的注入与脱出，通过极化离子液体调控拓扑相转换材料在钙铁石和钙钛矿相之间的可逆转换，进而成功设计出综合性能优异的突触晶体管。

9Silicon Photomultiplier Technologies Developed at Fondazione Bruno Kessler

报告人：Alberto Gola，Fondazione Bruno Kessler

时间：10月17日（周四）10:00

单位：中科院高能物理所

地点：B326, main building

Since 2005, Fondazione Bruno Kessler (FBK, Trento) has continuously developed and improved its SiPM technology for a wide variety of applications, ranging from medical imaging to big science experiments and industrial applications. Current-generation Near Ultra Violet, High Density (NUV-HD) SiPM technology features a peak photon-detection efficiency (PDE) higher than 60% at 410 nm, low primary and correlated noise and is very well suited for medical imaging applications, such as time-of-flight positron emission tomography (TOF-PET). Indeed, using an advanced high-frequency readout, a research group at CERN demonstrated state-of-the-art coincidence resolving time of 58 ps FWHM, employing 4x4 mm2 NUV-HD SiPMs coupled to small LSO:Ce:Ca crystals. With a similar, optimized setup, a single-photon time resolution (SPTR) of 90 ps FWHM was also demonstrated, which is even more important when faint Cherenkov emission is used to improve timing performance in relatively slow scintillators such as BGO.
On the other hand, different applications require specific optimizations of SiPM parameters, especially in the field of big science experiments. To this end, several improvements of the NUV-HD technology are>At the lower-energy end of the sensitivity spectrum, we observe a growing interest from industry in using SiPMs for detection of near infrared light. Among different applications, the most important one is LIDAR, especially for advanced driver-assistance systems in the automotive field. NIR-sensitive SiPMs (NIR-HD) fabricated at FBK use a thicker epitaxial layer to enhance detection efficiency at longer wavelengths, achieving high PDE of 12 % 905nm, without micro lenses. Ongoing research is aimed at further improving this result by careful engineering of the SPAD structure.

10氧化物异质界面的原子构筑与调控

报告人：廖昭亮，中国科学技术大学国家同步辐射实验室

时间：10月17日（周四）15:00

单位：中科院物理研究所

地点：M236会议室

诺贝奖获得者Herbert Kroemer有句名言：“界面即是器件”。界面效应是许多半导体器件的核心。这句话在以关联电子效应为基础的氧化物异质结尤其如上。两种电子、晶格和化学成份各异的复杂氧化物材料组成异质界面后，界面的自旋、电荷、轨道以及晶格以及彼此之间的相互作用都会发生变化，从而产生完全不同于块材的丰富的物理现象，并很有潜力突破半导体材料，成为下一代电子学材料的核心载体。在这种新材料体系，我们可以充分地利用界面效应去原子级的精确设计和制备新材料。本次报告将围绕我们最近在这领域的一些工作介绍氧化物异质结新材料体系的制备方法、功能设计原理以及我们在磁性、电子相变方面取得的一些结果。主要内容包括钙钛矿氧化物界面的结构耦合效应、以及如何利用结构耦合效应进行新磁性材料的界面设计、电子相变的连续调控，并结合同步辐射表征方法、理论计算、高分辨微区晶体表征等先进的手段探讨界面新奇现象的物理机制。

11Prediction of Topological Materials: from physical intuition to routinely search

报告人：翁红明，中科院物理所

时间：10月17日（周四）16:00

单位：清华大学

地点：理科楼郑裕彤讲堂

Topological materials are solids with nontrivial topology in their electronic band structures. The periodical lattice of atoms in solids limits the electrons in a compact reciprocal lattice space and leads to nontrivial band topology in both insulators and metals, namely topological insulators and topological semimetals. Band inversion is an intuitive picture for understanding the underlying physics since it is related with Berry phase and Berry curvature of bands. How to find a material with nontrivial band topology had been a quite elusive and difficult task. However, some exotic and abnormal physical phenomena related with nontrivial band topology have been noticed and successfully applied for locating the exact topological materials, which includes a large band gap two-dimensional TIs in ZrTe5, the first Dirac semimetal Na3Bi and the first Weyl semimetal TaAs. These discoveries have greatly advanced the whole field of topological quantum states. Recently, the band inversion have been found to be efficiently identified with symmetry indicators formed by irreducible representation of bands at high symmetrical momenta, which can be obtained from first-principles band structure calculations. High-throughput calculation of known non-magnetic materials is thus performed and thousands compounds have been identified to have nontrivial band topology, which is put into a database for routinely search.

12Multiscale Photoacoustic Microscopy

报告人：Lei Xi ， Southern University of Science and Technology

时间：10月18日（周五）09:30

单位：北京大学

地点：物理楼西楼464

Photoacoustic microscopy (PAM), benefiting from rich optical contrast, scalable acoustic resolution and deep penetration depth, is of great importance for the fields of biology and medicine. The introduction of new scanning devices/mechanisms and fast pulsed lasers enables high spatiotemporal resolution and compact configuration. However, limited by the size and performance of reported optical/acoustic scanners, existing PAMs are bulky, heavy, and suffer from low imaging quality/speed. In this talk, I will present a multiscale photoacoustic microscopic platform consisting of large-field-of-view PAM, portable PAM, handheld PAM and endoscopic PAM, which are capable of meeting various requirements of both fundamental and clinical studies.

13Optical focusing, imaging and stimulation at depths in tissue

报告人：Puxiang Lai，Hong Kong Polytechnic University

时间：10月18日（周五）14:00

单位：北京大学

地点：物理楼西楼464

Light, in many ways, is an ideal form of electromagnetic waves to probe biological tissues as light can interact with almost all kind of molecules. Biomedical optical imaging, however, encounters an inevitable trade-off between resolution and penetration depth due to the strong scattering of light in tissue. Here we summarize our endeavors in the past years of using the synergy of light and sound to achieve high-resolution optical focusing, imaging, and stimulation within or through thick scattering media based on optical wavefront shaping and deep learning. Limitations, potential applications, and further direction are also discussed.

14Continuum naturalness

报告人：Csaba Csaki，Cornell University

时间：10月18日（周五）15:30

单位：中科院理论物理所

地点：ITP South Building 6620

更多报告信息：中国物理学会期刊网学术讲座列表

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