Editor's note: Recently, a good news from the scientific community came: the joint experimental team of the Chinese Academy of Physics and Tsinghua University observed the first quantum anomalous Hall effect in magnetically doped topological insulator films. . As soon as the news came out, the quantum concept stocks had a daily limit. Listed companies that have worked closely with the experiment in the A-share market are expected to make a big profit.
The Hall effect is a physical effect discovered by the American physicist Hall in 1879 more than 130 years ago. In a conductor carrying current, if a magnetic field perpendicular to the direction of the current is applied, due to the effect of the Lorentz force, the trajectory of electrons will be deflected, thereby generating a voltage across the conductor perpendicular to the direction of the current and the magnetic field. This phenomenon of electromagnetic transport is known as the Hall effect.
In 1880, when studying the Hall effect of magnetic metals, Hall discovered that the Hall effect can be observed even without an external magnetic field. This Hall effect in a zero magnetic field is an anomalous Hall effect. Anomalous Hall conductance is caused by the spontaneous magnetization of the material itself, so it is a new type of important physical effect.
In 1980 and 1982, German and American scientists discovered the integer quantum Hall effect and the fractional quantum Hall effect, and won the Nobel Prize in Physics respectively. Therefore, the quantum anomalous Hall effect is also regarded as "the last of the quantum Hall effect family" An important member ". Academician Xue Qikun of Tsinghua University, who led the experiment, said: "Physicists believe that quantum anomalous Hall effect should also exist in the quantum Hall effect family. But how to make it appear and observe it experimentally has become a condensed state in recent years One of the problems explored by physicists. "
Led by Academician Xue Qikun of Tsinghua University, a team composed of researchers from Tsinghua University, Chinese Academy of Sciences and Stanford University, the research report completed in 4 years successfully predicted the quantum spin Hall effect in two-dimensional topological insulators, and In 2008, the possibility of introducing magnetism into the topological insulator to realize the quantum anomalous Hall effect was proposed. In 2010, researchers Fang Zhong and Dai Xi from the Institute of Physics of the Chinese Academy of Sciences cooperated with Professor Zhang Shousheng to predict that Cr or Fe-doped Bi2Se3, Bi2Te3 and Sb2Te3 three-dimensional topological insulator films are the best system to realize the quantum anomalous Hall effect. It was published online in the US "Science" magazine on March 15. For the first time, Chinese scientists independently observed the quantum anomalous Hall effect experimentally, which is regarded as "an important scientific discovery in the field of basic research in the world."
Xue Qikun said that to achieve the quantization of the abnormal Hall effect experimentally, topological insulator materials are required to meet three very harsh conditions at the same time: the energy band structure of the material must have topological properties to have a conductive one-dimensional edge state; the material must have The long-range ferromagnetic sequence thus has an anomalous Hall effect; the body of the material must be in an insulated state so as not to contribute to conduction. In actual materials, it is quite difficult to achieve any of the above points, and meeting these three points at the same time is a huge challenge for experimental physicists. Scientists in Germany, Japan, and the United States cannot coexist in materials at the same time. Satisfying these three points without achieving final success.
The importance of the quantum Hall effect is that it may play a special role in future electronic devices, used to prepare high-speed electronic devices with low energy consumption, thereby promoting the progress of information technology. However, because the generation of ordinary quantum Hall effect requires the use of a very strong magnetic field (usually required magnetic field strength is tens of thousands or even hundreds of thousands of times that of the geomagnetic field), it is very expensive and difficult to apply; and its bulky (closet Size) is not suitable for personal computers and portable computers.
The most beautiful thing about the quantum anomalous Hall effect is that it does not require any external magnetic field. It is possible for humans to use their non-dissipative edge states to develop a new generation of low-power transistors and electronic devices to solve computer heating problems and Moore ’s Law. Bottleneck problem. This is why scientists from all over the world pay special attention to the quantum anomalous Hall effect. Therefore, this research will promote the development of a new generation of low-power transistors and electronic devices, and may accelerate the progress of the information technology revolution.
A team led by Academician Xue Qikun of Tsinghua University used molecular beam epitaxy to grow a high-quality magnetic doped topological insulator film, prepare it as a transport device, and perform its magnetoresistance and anomalous Hall effect in an extremely low temperature environment. Precise measurement finally found that within a certain range of applied gate voltage, the anomalous Hall resistance of this material in the zero magnetic field reached the characteristic value of the quantum Hall effect. World problems can be overcome.
Researchers from Tsinghua University and the Institute of Physics of the Chinese Academy of Sciences have cooperated closely and coordinated innovation. Since 2009, the experiment of the vector anomalous Hall effect has been launched. Over the past four years, the team has grown and measured more than 1,000 samples, overcoming many obstacles, and has achieved the growth of high-quality thin films of magnetically doped topological insulators, the observation of surface electronic states, especially the electronic structure and magnetic order The precise control of the state and energy band topology finally observed the quantum anomalous Hall effect in October 2012, which also confirmed the previous predictions made by the theoretical team of the Institute of Physics of the Chinese Academy of Sciences and Stanford University.
Nobel Prize winner Yang Zhenning attended today's press conference. He said that the paper on discovering the quantum anomalous Hall effect is a physics paper made by a Chinese laboratory with a Nobel Prize. "This is not only a happy event for Tsinghua University and the Chinese Academy of Sciences, but also a great event for the development of the entire country."
Driven by the success of Tsinghua University ’s quantum anomalous Hall effect experiment, A-share listed companies that are relevant to the experiment and have close cooperation with Tsinghua University ’s scientific research are worthy of attention, such as variety arts shares, Fujing Technology, and Tongfang shares.
Variety Shares (600770): The company established Variety Superconducting Technology Co., Ltd. in November 2006 with Tsinghua University and other joint ventures to develop high-temperature superconducting filter technology (accounting for 44% of the shares). Currently, only the company can fully own intellectual property rights and product production capacity. The United States and China, the high-temperature superconducting project is a national 863 major project, with complete independent intellectual property rights. In 2012, the company's high-temperature superconducting filter system achieved large-scale commercial application. The project leader was Cao Bisong, a professor of the Department of Physics of Tsinghua University. The academician Xue Qikun of the Department of Physics of Tsinghua University led the discovery of the quantum anomalous Hall effect. In-depth research has been carried out on the molecular beam epitaxial growth and superconductivity of thin films. In the future, for the commercial application of scientific research results of the Physics Department of Tsinghua University, the company has obvious first-mover advantages due to its long-term cooperative relationship.
Fujing Technology (002222): a listed company under the Chinese Academy of Sciences, mainly engaged in the research, development, production and sales of nonlinear optical crystals, laser crystals and precision optical components. The company is the world's leading manufacturer of nonlinear optical crystals and laser crystal components. The world's largest manufacturer of LBO, BBO nonlinear optical crystal components, Nd: YVO4 laser crystal components and Nd: YVO4 KTP cemented crystals is the largest manufacturer of KTP nonlinear optical crystal components in China. As a listing platform under the Fujian Institute of Material Structure of the Chinese Academy of Sciences, the company actively extends the industrial chain by undertaking the scientific research achievements of major shareholders to cultivate new growth points for the company. The stock quickly rose late in the day yesterday and rose 1.57% at the close.
Tongfang (600100): Relying on the scientific research strength and talent platform of Tsinghua University, the company continues to explore and innovate in the two industrial directions of information, energy and environment around the development strategy of "technology + capital, cooperation + development and brand internationalization" It has formed a development pattern centered on ten major industries such as computers, digital cities, Internet of Things applications, microelectronics and radio frequency technology, multimedia, semiconductors and lighting, knowledge networks, military industry, digital television, and environmental technology. This major discovery by the professor of Tsinghua University will play a leading role in the industrialization of future science and technology. The stock rose slightly yesterday and closed up 0.86%.
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