TALENT EDUCATION

Peking University performs a “hat-trick” in Nature!


On the evening of March 22, Nature’s official website published a number of papers

The three achievements of Peking University were published online at the same time

Staging a “hat-trick”

Research Group of Junyu Xiao, Research Fellow, School of Life Sciences

Publish results

FcμR receptor recognition of immunoglobulin IgM

Professor Peng Hailin’s research group in the School of Chemistry and Molecular Engineering

Publish results

“Epitaxial High κ Gate Oxide Integrated Two-Dimensional Finned Transistor”

Professor Peng Lianmao-Qiu Chenguang Research Group, School of Electronics

Publish results

《Two-dimensional indium selenide ballistic transistor》

Reveal, break through!

Xiao Junyu’s research group revealed the molecular mechanism of FcμR’s specific perception of different forms of IgM through structural biology, biochemistry and cell biology, laying a foundation for in-depth understanding of the biological function of IgM.

IgM is one of the five types of immunoglobulins in the human body, mainly secreted and synthesized by plasma cells in the spleen and lymph nodes, with powerful bactericidal, complement activation, immune conditioning and agglutination effects, and plays an important role in the early stage of immune response. FcμR (also known as Toso or Faim3) is the only IgM-specific receptor in mammals that binds to different forms of IgM, including membrane-bound IgM monomers, IgM pentamers and hexamers in serum, and secretory IgM, thereby participating in processes such as B cell development, immune system homeostatic regulation, and antigen presentation. In patients with chronic lymphocytic leukemia, the high expression of FcμR on the surface of B cells also reflects its importance in the immune system and disease development. However, in the past, the molecular mechanism by which FcμR functioned was not clear.

The latest work of Xiao Junyu’s group, “Immunoglobulin M perception by FcμR” (FcμR receptor recognition of immunoglobulin IgM), was published online in Nature on March 22, revealing the molecular mechanism by which FcμR recognizes different forms of IgM. This is another major breakthrough after Xiao Junyu’s research group published a paper in Science in 2020 to clarify the molecular mechanism of IgM pentamer assembly and mucosal transport.

In order to explore the recognition mechanism of FcμR to different forms of IgM, this study first recombined, expressing the complex of FcμR-D1 domain and IgM-Cμ4 domain, and resolved their crystal structure. Next, cryo-EM was used to resolve the complex structure composed of the core region of IgM pentamer and the extracellular domain of FcμR. Furthermore, cryo-EM was used to resolve the complex structure formed by FcμR and secretory IgM core region. In order to evaluate the functional relevance of the above study, FcμR mutants were designed and verified by in vitro protein interaction, fluorescence confocal microscopy, flow cytometry and other methods.

In conclusion, this study reveals the molecular mechanism of FcμR’s specific perception of different forms of IgM through structural biology, biochemistry and cell biology, which lays a foundation for in-depth understanding of the biological function of IgM.

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Screenshot of the research result Nature

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Recognition models of membrane-bound IgM, IgM pentamers, and secreted IgM by FcμR receptors

Xiao Junyu, a researcher from the State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, and Tsinghua Joint Center for Life Sciences, Peking University, is the corresponding author of the paper. Yaxin Li, a postdoctoral fellow at Peking University, Shen Hao, a 19th-level doctoral student in the School of Life Sciences, and Zhang Ruixue, a 19th-level doctoral student from the Institute of Frontier Interdisciplinary Research, are the co-first authors of the paper. This research was also supported by the Qidong Industrial Innovation Fund of the School of Life Sciences of Peking University, Changping Laboratory, China Postdoctoral Science Foundation (Boxin Program), and Peking University Liberal Arts Postdoctoral Program.

Solve the focus of “old and difficult”

Peng Hailin’s research group reported the world’s first high-extension κ-gate dielectric integrated two-dimensional fin transistor. This original work breaks through the bottleneck of two-dimensional new material precision synthesis and new architecture integration of high-speed and low-power chips in the post-Moore era, and brings new opportunities for the development of future advanced chip technologies.

In recent years, China’s “chip shortage”, the “old and difficult” problem, has repeatedly become the focus. In order to loosen the hand of the “stuck neck”, Peking University people have been forging ahead on this thorny road, striving to contribute to the iterative upgrading of China’s integrated circuit technology. On March 22, 2023, Professor Peng Hailin’s research group from the School of Chemistry and Molecular Engineering of Peking University published a research paper entitled “2D fin field-effect transistors integrated with epitaxial high-κ gate oxide” online in Nature. This study reported the world’s first epitaxial growth of a two-dimensional semiconductor fin/high κ gate oxide heterojunction array and its integrated preparation of a three-dimensional architecture, and the development of a high-performance two-dimensional fin-effect transistor (2D FinFET).

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Screenshot of the research result Nature

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Schematic of a high κ-gate oxide integrated 2D fin transistor (2D FinFET).

Professor Peng Hailin’s research group of Peking University has long been engaged in the research of physical chemistry and surface interface regulation of two-dimensional materials, and is committed to solving challenging international frontier scientific problems. Recently, they have been working to precisely integrate high-mobility two-dimensional semiconductors with high-κ-gate media and limit scaling into a new three-dimensional architecture. Professor Peng Hailin’s research group has established a unique way to establish an epitaxial growth method for wafer-level two-dimensional semiconductor Bi2O2Se vertical fin arrays on insulated substrates. At the same time, the controlled oxidation method is used to realize the epitaxial integration of two-dimensional Bi2O2Se fin/high κ autooxide Bi2SeO5 heterojunction. The new 2D semiconductor channel/epitaxy integrated high κ gate dielectric-based 2D fin transistor meets the industry’s requirements for high-performance and low-power devices in terms of mobility (270cm2/Vs), off-state current (1 pA/μm), and current switching ratio (108). In terms of open-state current density, Bi2O2Se/Bi2Se5 two-dimensional fin transistors also show electronic advantages and potential compared to materials such as commercial silicon, germanium and two-dimensional transition metal sulfide (TMD).

Professor Peng Hailin of Peking University is the corresponding author of the paper, and Tan Congwei, postdoctoral fellow at BMS Fellow, School of Chemistry and Molecular Engineering, Peking University, and doctoral students Yu Mengshi, Tang Junchuan, and Gao Xiaoyin are co-first authors. The main collaborators in growth theory calculation and morphological characterization also include Professor Ding Feng of the National Institute of Science and Technology, Ulsan, South Korea, and Professor Jiang Kaili of the Department of Physics, Tsinghua University. The research results have been supported by the National Natural Science Foundation of China, the Ministry of Science and Technology, the Beijing National Research Center for Molecular Sciences, the Tencent Foundation, the Postdoctoral Program of Peking University, the Postdoctoral Program of the Beijing National Research Center for Molecular Sciences, and supported by the Molecular Materials and Nanoprocessing Laboratory (MMNL) instrument platform of the School of Chemistry and Molecular Engineering of Peking University.

The fastest in the world so far!

Professor Peng Lianmao-Qiu Chenguang’s research group has made the actual performance of two-dimensional transistors exceed Intel’s commercial 10nm node silicon-based fin transistors for the first time, and the operating voltage of two-dimensional transistors is reduced to 0.5V, which is also the world’s fastest and lowest energy consumption two-dimensional semiconductor transistors.

Chips provide a steady stream of power for the development of big data and artificial intelligence, and the improvement of chip speed benefits from the scaling of transistors, but the performance of traditional silicon-based field-effect transistors is gradually approaching their intrinsic physical limits. To date, all 2D transistors have achieved performance comparable to the industry’s advanced silicon-based transistors, and their experimental results lag far behind theoretical predictions.

Recently, Professor Peng Lianmao-Qiu Chenguang’s research group of Professor Peng Lianmao of the School of Electronics of Peking University prepared a 10nm ultra-short channel ballistic two-dimensional indium selenide transistor, which has become the world’s fastest and lowest energy consumption two-dimensional semiconductor transistor so far. The study, titled “Ballistic two-dimensional InSe transistors,” was published online March 22 in Nature.

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Screenshot of the research result Nature

This work has achieved three technological innovations: first, the use of three-layer indium selenide with high carrier thermal velocity (smaller effective mass) as the channel has achieved the highest value of the current field-effect transistor; Second, it solved the problem of growing ultra-thin oxide layer on the surface of two-dimensional materials, and prepared 2.6nm ultra-thin double-gate hafnium oxide, which raised the transconductance of the device to 6 mSsie microns, exceeding all two-dimensional devices by an order of magnitude. Finally, the doping-induced two-dimensional phase transition technology was created, which overcame the international problem of gold half-contact in the field of two-dimensional devices, and refreshed the total resistance to 124 ohms·microns.

This work breaks through the key scientific bottleneck that has long hindered the development of two-dimensional electronics, pushes the performance of n-type two-dimensional semiconductor transistors to the theoretical limit for the first time, and is the first to experimentally prove that two-dimensional devices are superior to advanced silicon-based technologies in terms of performance and power consumption, which injects strong confidence and vitality into the development of two-dimensional semiconductor technology.

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Outlook: Faster and more power-efficient low-dimensional semiconductor chips

Jiang Jianfeng and Dr. Xu Lin are the joint first authors, Professor Peng Lianmao and Professor Qiu Chenguang are the co-corresponding authors, and the School of Electronics of Peking University is the only unit of the paper.

Behind each article, the painstaking efforts of every member of the team are condensed, and it is the most dazzling crystal produced by dozens of Peking University people after countless failures and sleepless nights. Peking University is often new. The research results are clear testimonies, telling the original intention and mission of Peking University people to promote the development of science and seek the progress of mankind.

In the future, expect more “hat-tricks” to be staged one after another. Peking University people will become more and more courageous on the road of scientific research and often climb the peak!
 
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