Great Country Academician

In the office, Xu Chuan fell into deep thought.

On the side, Fan Pengyue and Song Wenbo didn't dare to interrupt the boss's thinking, so they could only wait quietly on the side.

After clearing the thoughts in his mind, Xu Chuan raised his head, looked at Song Wenbai with shining eyes, and said:

"Professor Song, for the next period of time, you and your team temporarily stop the research on the copper-carbon-silver composite material, and turn your full attention to the analysis of the ultra-low temperature superconducting copper-carbon-silver composite material you have previously studied."

"I need more information and analysis data for this material!"

Hearing this, Song Wenbo was stunned for a moment, then quickly nodded and replied: "It's okay to turn away from research and turn to analysis. It's just to analyze materials. The equipment in our research institute may still be lacking."

"For example, there are no pyrolysis chromatographs for characterization and structural analysis, and inductively coupled plasma emission spectrometers. Without these equipments, the analyzed data is not perfect."

Xu Chuan: "This is no problem. Fan will always communicate with you about the relevant equipment. Buy what you should buy. Equipment is not a one-time purchase."

Fan Pengyue nodded and said: "The research institute has not been expanded for a long time, and it is true that some equipment has not been purchased yet, but this has been arranged in the procurement plan. It is just that the priority was lower before. Now that it is needed, it can be used in advance. Purchased."

Xu Chuan: "If it takes a long time to buy new ones, you can try to buy second-hand ones from other domestic laboratories. It doesn't matter if the premium is higher, I need to get the data as soon as possible."

In the conference room, Xu Chuan asked some more questions about the experimental data of the ultra-low temperature superconducting copper-carbon-silver composite material, and then left the Chuanhai Materials Research Institute with some data.

Back at the villa, he inserted the USB flash drive in his hand into the computer, took out a stack of manuscript paper from the drawer, sat at the desk and continued to meditate.

Since H. Catherine-Onnes discovered that metal elements such as mercury and tin have superconductivity in 1911, there have been dozens of metal elements that exhibit superconductivity under normal pressure.

As for the classification of superconductor materials, there is no uniform standard at present.

In general, the most common classification is based on temperature.

Superconducting materials that need to be frozen with liquid helium to reach the critical Tc are called low-temperature superconductors; those that are frozen with liquid nitrogen are called high-temperature superconductors; those that can reach superconductivity at room temperature are called room-temperature superconductors .

At present, apart from using the BCS theory to explain low-temperature superconductivity, there is no perfect and unified explanation for why superconductivity can be achieved at high temperature and room temperature.

As far as materials science is concerned, it is normal to get out materials by accident first, and then analyze the materials to find the mechanism.

In later generations, when he developed copper-carbon-silver composite materials, he also tried to explore and explain the basic principles of high-temperature and room-temperature superconducting materials.

But in the end, I didn't get an accurate answer. In addition, I didn't have time to study controllable nuclear fusion and NS equations, so I gave up exploring this aspect.

Of course, he didn't study it in his previous life, but it doesn't mean that no one studies the mechanism of high-temperature superconducting materials.

The mainstream view in later generations is that the superconducting pairing of cuprate high-temperature superconductors does not originate from the traditional BCS electroacoustic coupling, but from the strong correlation effect between electrons.

When studying physics in high school, we easily know that each atom has a different number of electrons outside the nucleus.

For example, an oxygen atom has eight positively charged protons outside the nucleus, and a carbon atom has six electrons outside the nucleus.

Under normal circumstances, the electrons in the solids composed of these atoms are very stable, and each electron is regarded as independent and will not affect each other.

Just like the eight planets in the solar system, each planet has its own independent orbit and will not collide together.

However, in many substances, such as transition metal oxides, lanthanide oxides and other atoms, the outer electron orbitals overlap greatly, and the electrons on the orbitals are close to each other, and the increase in electrostatic energy cannot be ignored.

These materials then have a strong correlation effect.

The strong correlation effect between electrons is the cause of many novel physical phenomena.

Such as fractional quantum Hall effect in two-dimensional electron gas, giant magnetoresistance effect in manganese oxide materials, heavy fermion system, metal-insulator phase transition in two-dimensional high mobility materials, etc.

Therefore, in later generations, for the superconducting mechanism of high-temperature superconductivity and room-temperature superconductivity, the mainstream is explained by the strong correlation effect of electrons.

It's just this kind of explanation, it's just a theory, and it can't be explained by models or mathematics.

But today, Xu Chuan felt that he might have a try.

Flipping through the experimental data of the low-temperature copper-carbon-silver composite material researched by Song Wenbo on the computer, Xu Chuan looked at it carefully, and prepared to deduce the mechanism of high-temperature superconductivity after getting familiar with it.

At this moment, the phone on the desk rang, and he picked up the phone. The call was from Gao Hongming.

"Academician Xu, the application for the Gucheng Supercomputing Center has already been submitted, and the time is five days later. After five days, the Tianhe-1 supercomputer of the Gucheng Supercomputing Center will deploy the computing power you need to simulate the operation in your hands. mathematical model."

On the phone, Gao Hongming replied with an application.

Xu Chuan nodded and said, "I see, I will go there on time."

After hanging up the phone, he looked at the data on the computer and picked up the pen next to the manuscript paper.

"In five days, you should be able to find some directions?"

Xu Chuan murmured softly to himself, and without thinking about it, he began to calculate on the manuscript paper with the pen in his hand.

"As shown in Figure 1, the low-energy physics of the layered structure is mainly determined by the CuO2 plane. On the CuO2 plane, the copper atoms form a square lattice, and there is an oxygen atom between the two nearest neighbor copper atoms. From the electronic From a structural point of view, the electron orbitals involved are mainly the 3d orbitals of copper and the 2p orbitals of oxygen”

"When the parent material is doped with a certain concentration of holes, it will enter the superconducting phase at low temperature, which can be explained in mathematical language as:"

"H=μd, σ∑iσDi, σdiσ+μp, σ∑IσPI, σP, σ-∑.PI↑Pi↓."

"Considering the single-band Hubbard model of the copper 3dx2-y2 orbital, the hole doped in the oxygen 2p orbital will form a spin singlet bound state with the hole in the copper 3dx2-y2 orbital, that is, the famous Zhang-Rice singlet .”

"The establishment of a low-energy effective model for it is the t-J model, and the calculation of the Hamiltonian is:

Ht-j=-∑, σtijPg(Ci, σCj, σ+h.c.)Pg+J∑Si·Sj"

In the study, Xu Chuan looked at the data on the computer while checking the strong electron correlation structure in the copper-carbon-silver composite material.

Using mathematics to calculate physics is a breakthrough in the deep research of mathematics in his life, and it is also one of his current best research.

Immersed in it, he calculated the data and integrated the thoughts in his mind.

This is a road to explain the mechanism of high-temperature superconductivity. Someone has gone through it before, but it has only opened up a short distance. Now, he is advancing.

Walking on this primitive road, the powerful mathematical ability in this life is the hatchet in his hand, overcoming obstacles; while the research on physics in the previous life is more like a compass, guiding the direction and ensuring that he will not open up wrong paths. the way.

The perfect combination of mathematics and physics, the last time it promoted the calculation of particle information in the field of high-energy physics, and this time, it is going deep into the subject of materials to explore the mysteries between atoms and electrons.

Bit by bit, Xu Chuan only had the pen and paper on the desk in his eyes. At this moment, he seemed to be walking in the dark, and there was darkness in front of him. Only a lighthouse shining in the distance guided him in the direction he was going.

As the days passed, outside the window, the weather in the deep winter was abnormally heavy, and the sky was covered with dark clouds, covering the earth.

I don't know how long it took, but the rain finally stopped, and the sun was moving, trying to penetrate the dark clouds and sprinkle its brilliance back to the world.

In the study, at some point, he stopped the pen in his hand, stood by the window and looked at Xu Chuan in the distance, and was fascinated by the rays of light falling on the ground through the dark clouds after the rain.

Looking at the sunset slowly setting in the sky, Xu Chuan smiled.

When the Tyndall effect occurs, light takes shape.

The light that shines from the sky after the rain is leading the direction of civilization.

Although he did not find the superconducting mechanism of high-temperature superconductivity, he has found a feasible path.

The rest is to continue along this road.

If the mechanism of high-temperature superconductivity can be completed, in the future, he may be able to obtain the superconducting state of high-temperature superconducting materials through mathematical calculations.

By that time, superconducting materials will no longer be an obstacle to the development of science and technology.

Even, maybe he can continue to deduce it, find new and better room temperature superconducting materials, and use them widely in all walks of life.

After all, the properties of the copper-carbon-silver composite materials developed by his later generations are somewhat biased towards ceramic materials. Although they can achieve superconductivity under normal temperature and pressure, they are difficult to process and easily disturbed.

This kind of restricted room-temperature superconducting material is not bad for controllable nuclear fusion and particle colliders, but it is still very difficult to widely use it in power generation, power transmission, energy storage, weak electricity and other fields. difficult.

Especially those equipments with relatively bad working environment are even more unusable.

If a room-temperature superconductor similar to copper-iron metal materials can be found, the existing scientific and technological development will usher in a real leap.

After thinking about it, Xu Chuan turned around and picked up the phone from the desk, found Gao Hongming's number and dialed it.

In less than half an hour, Gao Hongming rushed over from the controllable nuclear fusion industrial park.

"Academician Xu, you are looking for me."

Xu Chuan nodded, picked up the prepared hard drive and handed it over: "This one contains a mathematical model for the plasma turbulence in the chamber of a controllable nuclear fusion reactor."

"Originally, I planned to go to Gucheng to check the calculations in person, but now the situation has changed, and I have some other things in hand, so I am not going to go there in person. Please take this hard drive for a trip. "

Hearing this, Gao Hongming quickly said: "It's not a thing to take a trip, but if you don't go, I don't know anything about mathematical models and testing."

"If you really can't get away, let me give feedback to the higher-ups? Postpone a little time? It doesn't matter."

Xu Chuan thought for a while, and said, "Postponement is not the solution. How about this, I'll call Academician Peng Hongxi and ask the two people in charge of the modeling department to come out and accompany you over there."

"This model was optimized by them, and they are professionals in modeling, who can replace me in the past."

"If there is any problem at that time, you can also call me."

Gao Hongming thought for a while and said, "It's fine, but if you don't go, I'm still a little uncertain. After all, this matter is so important."

Xu Chuan smiled and said, "If everything goes well, I won't be able to do much. Just bring back the data after the model has been checked."

Gao Hongming nodded and said, "Okay, since that's the case, then I'll go to Academician Peng first."

Xu Chuan: "Thank you for your hard work, and have a good journey."

Gao Hongming carefully put the hard drive in his hand into the anti-collision box he brought, and said, "I just did some odd jobs, Academician Xu, you are the real hard worker."

"Since you still have something to do here, I won't bother you any more."

"In addition, my side will notify the people on the side of the army, and ask them to arrange people to accompany me to escort this model to Gucheng safely."

"Don't worry, the model is there!"