I just want to be a quiet scholar

Chapter 400 Teaching

通过对LaAlO3/SrTiO3异质界面、非晶合金Zr41.2Ti13.8Cu12.5Ni10Be22.5、致热相变金属氧化物二氧化钒等凝聚态物质的实验研究，杨定天采集了大量的实验数据，交给沈奇构建理论体系。

Yang Dingtian regards the laboratory as his home. Apart from going back to the dormitory to take a hot bath, he eats, drinks and sleeps in the Shenqi Mathematics Research Center.

Shen Qi finally understood why Yang Dingtian wanted to keep a cat. Yang Dingtian, an experimental madman of the abstinence department, needed a small healing animal to accompany him, otherwise he would be too lonely.

According to the laboratory data, Shen Qi began to draft a review article. Taking LaAlO3/SrTiO3 as an example, he agreed that the origin mechanism of the quasi-two-dimensional electron gas q2DEG with high concentration and high mobility at the heterogeneous interface is polarization catastrophe.

The polarization catastrophe theory was not proposed by Shen Qi, but he verified the theoretical support of the polarization catastrophe theory to q2DEG in his own way.

What is the practical application after verification?

Shen Qi wrote in the review article that new oxide materials may be put into the R&D and manufacturing of electronic devices in the future, and the traditional electronics industry may usher in new changes. Of course, the commercial application of q2DEG materials still needs further development. research, this field has broad application prospects.

For the research on vanadium dioxide (VO2), another oxide, based on certain experimental data and computer simulation data, Shen Qi boldly put forward a new conjecture based on the classical theoretical system of topological and geometric properties of defects. Let's call it "disorder-order phase transition rules of compounds with multiple crystal phase structures".

VO2 is a typical compound with multiple crystal phase structures. Around 341K, that is, 67.85 degrees Celsius, VO2 will undergo a reversible transition from a low-temperature insulator phase to a high-temperature metal phase, accompanied by reversible mutations in optical, electrical, and magnetic properties.

This unique property makes VO2 have broad application prospects in the fields of photoelectric material switches, smart glass, storage medium materials, and laser protection.

The metal-insulator reversible phase transition of compounds like VO2 has always been a hotspot of research by scientists, but its phase transition mechanism has not yet been determined.

Through research, Shen Qi found that the macroscopic physical phenomena of compounds with multiple crystal phase structures are determined by their microstructure characteristics. A large number of ordered core regions will be formed in the initial stage of phase transition. The interweaving of domains is disordered.

After rigorous topological analysis, Shen Qi speculated that the formation of superlattice is the result of ordering, which is conducive to our control of the metal-insulator reversible phase transition, which theoretically follows a one-dimensional lattice model.

Through tireless mathematical and physical calculations and optimization of the calculation method of lattice dynamics, Shen Qi gave the basic equation of this model:
∫+∞-∞dux/dx/x-ζdζ=(1-v)b/2asin4πux/b
"I'm exhausted, it's too brain-burning." Shen Qi conceived for several months, recruited a doctoral student to help him with experiments day and night, and finally wrote a review article of more than fifty pages.

More than half of the content in this article is filled with various experimental data, charts, and pictures, and a small half is theoretical analysis and speculation. The conclusive content is the final basic equation.

Shen Qi asked Yang Dingtian to come to the director's office to enjoy his newly published review article.

Yang Dingtian came in with the cat in his arms. After seeing Shen Qi's masterpiece, Yang Dingtian was shocked: "Director Shen is awesome, with a mere 500 million funding, you just fiddled with research results worth more than 50 billion."

The cat was also shocked: "Meow!"

"God, this is also due to your contribution. What I want to say is that this is only a phased research result, and your experiment will continue. This disorder-order phase transition rule has been verified by me repeatedly, and it can only be applied to some Oxides and complex oxides, even if the object is an alloy with a similar structure, it is not suitable." Shen Qi touched the cat's chin and said: "This cat has grown fat again, it seems that our center treats you well."

"So Director Shen will publish this review article?" Yang Dingtian asked.

Shen Qi converted the review article into PDF format and entered the submission page of "Physical Review Letters": "Send."

"My name is still in the list of authors?" Yang Dingtian shuddered, and he could see his inner excitement. Many doctoral students dare not think about being able to become the author of a PRL paper during the reading stage.

"I wrote the article, and you basically did the experiment. Your name must be included in the list of authors. Our 973 project is a series, and this review article is part of the series. As the experiment progresses, follow-up we There will also be sequels and extra episodes. Since you are just here, I will write the first article of this series. I hope you can grow up as soon as possible. You will be the editor of the subsequent sequels and extra episodes, and I will be responsible for the review." Shen Qi completed the review. After the article is submitted, forward the PDF file to Yang Dingtian's mailbox.

After finishing the work, Shen Qi handed some draft paper manuscripts to Yang Dingtian: "PDF is the presentation of the results, and these manuscripts represent the thinking process. You can take it back and study it. If you don't understand, you can ask me."

Shen Qi has his own way of leading doctoral students. Doctoral students should not be regarded as wage earners or experimental dogs. The most important thing is to impart experience and knowledge.

Yang Dingtian took over the manuscript as a treasure, and he also made a suggestion: "Our previous experiments were mainly to provide data support for theoretical construction. Now that we have a preliminary theory, should our next experiments be mainly applied research? For example, based on Director Shen’s disorder-order phase transition rules, we have obtained commercial application data of vanadium dioxide reversible phase transition through experiments, which can be applied in many industries such as construction, electronics, automobiles, high-tech industries, and even military industries. This thing is a patent, the wider the application and the higher the value, the more valuable it will be."

"I understand the truth, but do you think we can complete commercial R&D with only 500 million basic equipment and two guns? Of course, in the early stage, we can find some financially strong companies through industry-university-research cooperation. Partners, our center has grown stronger in the later stage, and we can work alone. But no matter how we work alone, we will not face the market directly. Market competition is the responsibility of enterprises, and universities and scientific research institutions are responsible for technical support. Remember, we are scientific researchers. Not a businessman." Shen Qi has his plan, he trains scientists, not business elites.

Yang Dingtian returned to the laboratory to continue doing experiments, and digested and absorbed the theoretical knowledge taught by Shen Qi.

Shen Qi deduced the disorder-order phase transition rules and the basic mathematical and physical equations of the one-dimensional lattice model, which consumed a lot of internal energy. He needed to relax and then devote himself to the next stage of research work.

(End of this chapter)