Institute of Physics, Chinese Academy of Sciences: the 90-year quest for research excellence

The history of the Institute of Physics (IOP), Chinese Academy of Sciences (CAS), dates back to 1928–29, when the Institute of Physics, Academia Sinica was founded in 1928 and the Institute of Physics, National Academy of Peiping was founded in 1929. These two predecessors merged in 1950 to form the Institute of Applied Physics (IOAP). The present name, IOP, was then adopted in October 1958.

Through the steadfast efforts of generations of scientists, IOP has become a comprehensive and multidisciplinary research institution engaged in the basic and applied research of condensed-matter physics, optical physics, atomic and molecular physics, plasma physics, soft-matter physics and computational physics. By designation of the Ministry of Science and Technology of China, IOP is also known as Beijing National Laboratory for Condensed Matter Physics (BNLCP, inaugurated in 2013) and the National Research Center for Condensed Matter Physics (NRCCMP, approved in November 2017).

Presently, IOP is host to three state key laboratories, seven CAS key laboratories and two IOP key laboratories. IOP has also set up seven cross-disciplinary research centers for collaborations in essential research fields aiming for strategic national needs.

ALL FOR TALENTS

IOP makes great efforts in recruiting talents at different levels via different channels. Each year, IOP throws a reception at the annual American Physical Society (APS) March Meeting, which provides a convenient platform for overseas talents to find and negotiate a career with IOP.

IOP Recruitment Reception at APS March Meeting 2018 in Los Angeles, USA

Since November 2017, IOP has expanded its overseas recruitment efforts to cover more international conferences and overseas universities, including Harvard University, Stanford University, Max Planck Institute for Chemical Physics of Solids in Germany and the National University of Singapore.

IOP Recruitment Seminar at the Max Planck Institute for Chemical Physics of Solids in Berlin, Germany

IOP constantly explores ways to improve its academic environment and promote original scientific results. It organizes various lecture series such as ‘Daniel C Tsui's Lectures’, ‘ZGC Forums’, ‘Lectures on the Frontiers of Condensed Matter Physics’, ‘Lectures on Communal Technologies’, ‘Academic Talks in the House of Science’ and ‘Guest Talks: To Understand the Time & Space’, etc., which have greatly promoted an open and dynamic environment for academic exchanges.

IOP also devotes much attention to international collaboration. So far, many cooperative programs have been carried out and various agreements and memorandums have been signed with universities and laboratories in the USA, France, Britain, Germany and Japan, etc. On average, IOP researchers make more than 600 trips abroad for academic exchanges yearly and more than 500 foreign experts and scholars visit IOP each year.

A WORLD LEADING INSTITUTE FOR CONDENSED-MATTER PHYSICS

IOP is committed to research excellence in the frontiers of science and cutting-edge technologies, and has achieved a series of significant breakthroughs in condensed-matter physics, leading the research internationally. A few examples include the ‘Discovery of oxide superconductors at liquid nitrogen temperatures’, the ‘Discovery of Fe-based high-temperature superconductors with critical temperature (Tc) above 40 K and some of their basic physical properties’, the ‘Research on topological insulators and quantum anomalous Hall effect’, the ‘Discovery of Weyl fermions’, as well as the development and production of high-quality neodymium permanent magnets, lithium-ion batteries, single-crystal silicon carbide substrates and high-temperature superconductivity filters, etc.

REPRESENTATIVE SCIENTISTS AND WORKS

Highlight: Discovery of Weyl fermions in solids

After the discovery of Dirac semimetals Na₃Bi and Cd₃As₂, Zhong Fang and his team made another breakthrough in the study of topological quantum states. They predicted that TaAs family compounds are Weyl semimetals and then confirmed this with the observation of Weyl fermions in TaAs. This is the first time that the behavior of Weyl fermions has been seen since its proposal in 1929 by H. Weyl. This indicates the success in extending the topological classification of quantum matters from insulator to metal. Weyl semimetals are expected to be used for low-power-consumption electronic devices and topological quantum computing. These pieces of work have been selected as ‘2015 Top 10 Breakthroughs of the Year’ by Physics World (IOP Publishing) and the ‘Highlights of the Year in 2015’ by Physics (APS). In 2018, to celebrate 125 years of the Physical Review Journals, ‘Weyl fermions are observed in a solid’ has been selected as one of the work pieces of significance to physics and to the history of the APS.

Figure. Weyl fermions in solids. Reprinted from [Weng HM, Fang C and Fang Z et al. Phys Rev X 2015; 5: 011029].

Zhong Fang is the current director of IOP. He received his PhD degree in 1996 and joined IOP in 2003. His major research field is computational condensed-matter physics. Fang was the recipient of the International Centre for Theoretical Physics Prize (ICTP Prize) in 2008 and was selected as an APS Fellow in 2011.

Highlight: Looking into the superconductors with experiments

Zhou's group works on the development of vacuum-ultra-violet (VUV) laser-based angle-resolved photoemission systems with super-high resolutions and applies this technology in the study of high-temperature cuprate superconductors, Fe-based superconductors, and other quantum and topological materials. Taking advantage of the VUV laser-based angle-resolved photoemission system, he studied many-body effects extensively in high-Tc cuprate superconductors and identified new energy scales. He studied the electronic structure and superconducting gap of various iron-based superconductors and identified key electronic features that are responsible for superconductivity. In particular, by using the angle-resolved photoemission technique, he has successfully determined quantitatively the pairing interaction functions in the high-Tc cuprate superconductors that are significant in understanding the pairing mechanism of high-temperature superconductivity.

Figure. Color representation of the measured photoemission intensity of the underdoped Bi2212 superconductor (Tc = 89 K) along the momentum cut (red line in inset of (B)) at (A) T = 16 K; (B) T = 107 K. Adapted from [Bok JM, Bae JJ and Choi HY et al. Sci Adv 2016; 2: e1501329].

Xingjiang Zhou is now the director of the National Lab for Superconductivity of IOP. He got his PhD degree in IOP in 1994, and performed research in Germany and the USA before he went back to IOP in 2006. Zhou's research field is experimental condensed-matter physics. He was the winner of the TWAS (The World Academy of Sciences) Prize in Physics in 2015.

Highlight: Cool it down

In order to explore topological quantum states at ultra-low temperatures, Li Lu and his colleagues built the first nuclear demagnetization facility in China, and reached sub-mK lattice temperature in 2008. They further worked on cooling down the electrons in low-dimensional materials and devices. By developing particular techniques and paying special attention to filtering, screening, isolation and grounding, in 2010, Li Lu and coworkers reached the record of ∼4 mK electron temperature in 2D electron gas in high magnetic fields, which is among the lowest in the world. This facility will be used to study the possible non-Abelian statistics of the fractional Quantum Hall States, and to explore topological quantum computation based on these states.

Figure. A photo of the facility.

Li Lu is a low-temperature experimentalist. He joined IOP in 1986 and became a full professor in 1996. He is currently the chair of the Committee on Low Temperature Physics, the Chinese Physical Society (CPS). He is a fellow of APS and a fellow of IOP UK.

Highlight: High-energy-density lithium batteries

Recently, Li's team has endeavored to develop high-energy-density lithium-ion batteries and metallic-lithium batteries with hybrid solid/liquid electrolyte via an in-situ solid electrolyte interphase (SEI) growth strategy. First, the pouch cells of lithium-ion batteries or metallic-lithium batteries are fabricated using a similar method to commercial lithium-ion batteries. The specially designed liquid electrolyte is injected. Then, part of the liquid electrolyte converts into a solid phase at the anode and cathode side through SEI reactions. By tuning the type of solvents, salts and additives, as well as controlling the formation conditions, the weight ratio of the remaining liquid electrolyte in the cell can be tuned. The weight ratio of the liquid electrolyte in the cell could decrease to less than 10 wt%. By tuning the cathode and anode and their ratio, the Ah-level pouch cells have achieved energy density ranging from 260–573 Wh/kg and 600–1000 Wh/L with a reasonable cycle life.

Figure. New hybrid solid/liquid electrolyte-lithium batteries, in which composite lithium anode, solid-electrolyte-pasted separator and solid-electrolyte-coated cathodes are used. Supporting document in [Dominic B, Kei H and David H et al. J Power Sources 2018; 382: 176–8]

Hong Li is a professor in IOP. His research interest is high-energy-density lithium-ion batteries, solid-lithium batteries and failure analysis. Li is the regional editor of Solid State Ionics and Ionics and was awarded as distinguished young scientist by the National Natural Science Foundation of China (NSFC) and leading scientist of the national ‘Ten thousand plan’.

Highlight: Femtosecond laser facility: toward Peatwatt power with enhanced contrast ratio

The pursuit of the femtosecond high-power laser with unprecedented intensity is fantastic work. To generate an ultra-high-intensity femtosecond Ti: sapphire laser with high contrast for laser matter interaction experiments, Wei proposed a new scheme of combining Doubled Chirped Pulse Amplification (DCPA) and femtosecond Non-collinear Optical-Parametric Amplifier (NOPA). By using a sub-10 fs laser pulse from the home-made Ti: sapphire oscillator as the seeding, a 26 μJ signal with 10¹⁰ contrast was obtained after amplification by two-stage NOPAs that were synchronously pumped by the doubled-frequency Ti: sapphire laser from the first CPA. Further seeding the signal pulse into the second CPA and suppressing the parasitic lasing by special liquid material surrounding the Ti: sapphire crystal, a 32.3 J laser pulse with a duration of 27.9 fs was obtained, corresponding to a peak power of 1.16 PW (10¹⁵ W), which broke the world record of peak power from a Ti: sapphire laser facility.

Figure The XL-III femtosecond laser facility with a peak power of 1.16 PW.

Zhiyi Wei obtained his PhD degree in 1991 and is currently an IOP professor. Wei and his colleagues have made a series of progresses on generation, synchronization, amplification, frequency conversion and carrier envelop phase control of femtosecond lasers. He was elected as OSA (Optical Society of America) Fellow in 2017.

Highlight: Quasi-2D superconductivity in bulky AuTe₂Se_4/3

The emergent phenomena such as superconductivity and topological phase transitions can be observed in strict 2D crystalline matters. Artificial interfaces and one-atomic-thickness layers are typical 2D materials of this kind. Although having 2D characters, most bulky layered compounds, however, do not possess these striking properties. Chen and colleagues discovered the quasi-2D superconductivity in bulky AuTe₂Se_4/3, where the reduction in dimensionality is achieved through inducing the elongated covalent Te–Te bonds. The atomic-resolution images reveal that the Au, Te and Se are atomically ordered in a cube, among which are Te–Te bonds of 3.18 and 3.28 Å. The superconductivity at 2.85 K has been discovered, which has unraveled to be of a quasi-2D nature owing to the Berezinsky–Kosterlitz–Thouless topological transition. A dimensional reduction in the electronic structure has been proposed and hence the novel properties can be realized in bulky materials.

Figure. The stereotype structure of AuTe₂Se_4/3. Adapted from [Guo JG, Chen X and Jia XY et al. Nat Commun 2017; 8: 871].

Xiaolong Chen is the director of the Lab of Advanced Materials and Electron Microscopy of IOP. He has long been working on new materials exploration, property characterizations and crystal growth of wide-band-gap semiconductors. He is currently vice-chairman of the International Center for Diffraction Data.

DEVELOPMENT OF HUAIROU SCIENCE CITY

IOP is playing an important role in the development of Huairou Science City, which will host the National Science and Innovation Center. As part of the national and CAS R&D initiative, the following projects in Huairou Science City are undertaken by IOP.

Synergetic Extreme Condition User Facility (SECUF)

SECUF is a major project of the national infrastructure for scientific research. The aim is to develop the first-in-the-world synergetic user facility that integrates various extreme conditions such as ultra-low-temperature, ultra-high-pressure, ultra-high-magnetic-field and ultrafast optical fields. Upon completion, it will significantly strengthen China's research capacity for physical sciences, which may result in a chain of discoveries of new material states, phenomena and rules of matter. The construction of the project started in September 2017 and is expected to take 5 years to complete. The planned construction area is 48,000 square meters, with a total investment of 1.576 billion RMB (USD 250 million).

Center for Clean Energy 
(CCE)

CCE is a collaborative project between CAS and Huairou Science City. The aim is to build a multifunctional platform for the measurement, diagnosis and analysis of clean-energy materials, incorporating sub-platforms for the advanced testing and analysis of chemical-energy storage, physical-energy storage, solar cells and LEDs, as well as a synchrotron radiation beamline end station for clean-energy research. This center will be the first one in the world to be able to perform testing and analysis from the atomic to the macro scale, thus reinforcing China's innovative R&D as well as the testing of the safety and effectiveness of clean-energy materials and devices. The construction of the center started in May 2017. It is expected to cover 30,000 square meters and cost approximately 440 million RMB (USD 70 million).

Center for Materials 
Genome Initiative 
(CMGI)

CMGI is another collaborative project between CAS and Huairou Science City. The aim is to build the world's largest research center for material genomes by integrating three main research processes—computation, synthesis and characterization—so as to greatly accelerate the discovery of new materials and reduce the transition time between discovery and application. The construction of the center started in May 2017. It is expected to take the pilot run at the end of 2020. The planned construction area is 40,000 square meters, with an investment of 540 million RMB (USD 86 million).

Huairou Science City

INTERVIEWS

Zhongxian Zhao

Born in 1941; Academician of CAS; laureate of the National Preeminent Science and Technology Award (2016) for his pioneer work on 
high-temperature superconductivity.

Yupeng Wang

Born in 1965; former director of IOP; theoretical condensed-matter physics.

Jiangping Hu

Born in 1972; deputy director of IOP; theoretical condensed-matter physics.

Tian Qian

Born in 1980; professor of IOP; experimental condensed-matter physics.

Jinguang Cheng

Born in 1982; professor of IOP; high-pressure extreme condition physics.

NSR: Why did you choose IOP?

Zhao: Favorable atmosphere of science research.

Wang: IOP is the best institute for me.

Hu: Joining IOP is a very easy decision to make. IOP covers almost all the fields of condensed-matter physics with many world-class researchers. At this moment, there is no other place like IOP in China and very few ones in world.

Qian: There are two reasons for me to choose IOP. Firstly, I began to conduct angle-resolved photoemission spectroscopy (ARPES) experiments during my postdoctoral period in Japan. At that time, Prof. Hong Ding returned China from the USA and started to set up a research group in IOP and to construct experimental systems for ARPES, which, I thought, could provide strong supports for my research. Secondly, the IOP is the largest top-level research institution in China in the field of condensed-matter physics. Many scientists in different research directions in the field of physics have gathered in IOP. I can easily find suitable research directions and excellent collaborators.

Cheng: I chose IOP for the following reasons: (i) IOP can provide sufficient startup financial support to establish a research laboratory based on my own research interest; (ii) IOP has an excellent technical supporting platform to keep the subsequent research running smoothly; (iii) IOP offers a free academic atmosphere encouraging for the idea exchange and sharing.

NSR: How do IOP researchers communicate with scientists in other research directions?

Zhao: Communications of scientists from different fields often result in new inspirations.

Wang: Communications in IOP is perfect. Cooperation among scientists of different research groups is effective and efficient.

Hu: I have collaborated with many research groups in IOP. We constantly discuss and exchange research ideas in the IOP coffee room, lobby and conference rooms. IOP has the most dynamic and friendly research environment for scientists to communicate.

Qian: In fact, the different research directions in IOP are strongly complementary, resulting in many opportunities for collaboration, such as collaboration between theoretical calculations, sample synthesis and experimental measurements, as well as combination of experimental techniques between optics, extreme conditions and spectroscopy. In many cases, it is necessary for scientists in different directions to work together to complete a research work or to build experimental equipment. So, lots of scientists in IOP have a strong sense of collaboration. For example, the most common greeting when we meet is ‘what interesting things you are doing recently’. There are many academic seminars and lectures in different fields of physics every week. There are also several coffee rooms, which provide locations for scientists to communicate face to face and facilitate the collaboration between different research directions.

Cheng: There are quite close and intense communications among the scientists in IOP, leading to a new paradigm of whole-chain collaborative research by involving specialists in different fields. For example, an interesting problem started from the theoretical calculation/prediction can be quickly passed to the experimental realizations including sample preparation and various characterizations. It is such an excellent collaborative atmosphere that enables IOP to initiate some pioneering fields and to tackle down some difficult problems. In addition, IOP officially organizes the IOP Young Scientists Symposium twice per year to create opportunities for in-depth communications of scientists from different directions.

NSR: Would you please introduce one of your recent research accomplishments in IOP? How did IOP support your work?

Zhao: The technology platform has been providing solid and effective support to the research on high Tc Fe-based superconductors.

Wang: My work on off-diagonal Bethe Ansatz solved a long-standing problem in mathematical physics. I had concentrated on this work for many years, which wouldn’t be possible if the evaluation system of IOP had emphasized on quick success and instant benefits.

Hu: I am extremely excited about the possible existence of electronic genes for unconventional high-temperature superconductors and the possibility to make successful material predictions following this idea. This idea stems from enormous discussions and collaborations with my colleagues at IOP. I believe that it is very likely that they will eventually confirm or falsify my predictions as well.

Qian: Since 2015, I started to study topological quantum states of matter and have confirmed experimentally a series of topological materials using ARPES. The most prominent achievement for me is the first experimental confirmation of Weyl semimetal state. Our experimental work as well as the theoretical prediction of Weyl semimetal state made by our colleagues in IOP was highly recognized worldwide.

The whole work was composed of three steps: theoretical prediction, sample synthesis and experimental confirmation, which were completed by the collaboration between the scientists of three different research directions in IOP. I was in charge of the experimental measurement. The most important experimental data were recorded at the ‘Dreamline’ beamline, the construction of which was led by Prof. Hong Ding, at the Shanghai Synchrotron Research Facility (SSRF). It is a wonderful case that fully embodies how the scientists in different research directions in IOP do research with collaboration.

Cheng: My primary research interest focuses on the exploration of emergent quantum materials and phenomena under high-pressure extreme conditions. One of my current research directions is to discover novel unconventional superconductors by employing the high-pressure technique. Under the strong support of IOP, I established a unique cubic-anvil-cell high-pressure apparatus that enables us to discover the superconductivity in CrAs and MnP, which are respectively the first superconductor among the Cr- and Mn-based compounds. In recognition of these breakthroughs, I was honored the ‘Sir Martin Wood China Prize’ in 2016. I cannot accomplish these achievements without the strong support of IOP.

NSR: What are your future expectations of IOP?

Zhao: I hope to continue on extending our proven traditions to offer more support for young scientists and engineers.

Wang: I hope IOP will stick to the pragmatic evaluation system, getting away from exaggerating.

Hu: IOP has bright future. I feel that science in China just starts. I expect that IOP will be the international research center in condensed-matter physics and play a leading role in both fundamental and applied physics research.

Qian: I hope that IOP would create the first-rate achievements and pay the first-rate salary, which are the definition of ‘double first rate of IOP’, as said by Prof. Zhong Fang, the director of IOP. Moreover, I hope that IOP would more actively lead and participate in the construction of large research facilities in China, which are vital for the research in the field of physics and an important guarantee for IOP to keep the leading edge in the future.

Cheng: I joined the IOP in 2014. There are many young researchers from different fields joining the institute in the past 4 years. I hope that IOP will become a world leading institute for condensed-matter physics with the joint-effort of every individual of the institution.

Editor: Weijie Zhao.

Art editor: Xiaoling Yu.