In the office, Xu Chuan fell into deep thought.

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

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

"Professor Song, in the next period of time, you and your team will temporarily stop the research on copper-carbon-silver composites, and turn to the analysis of the ultra-low-temperature superconducting copper-carbon-silver composites you have researched before."

"I need more information and analysis on this material!"

Hearing this, Song Wenbai was stunned for a moment, and then quickly nodded and replied: "It's no problem to turn away from research and analysis, just analyze the materials, and the equipment of our institute may still be a little lacking." ”

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

Xu Chuan: "This is no problem, the relevant equipment Fan will always communicate with you, you should buy it, the equipment is this thing, and it doesn't mean that you only use it this time." ”

Fan Pengyue nodded and said: "The institute has only been expanded for a long time, and there is indeed some equipment that has not been purchased yet, but this has been arranged in the procurement plan, but it is said that the priority was lower before, and now since it is to be used, it can also be purchased in advance." ”

Xu Chuan: "If it takes a long time to buy a new one, you can try to buy a second-hand one from other laboratories in China." It's okay to have a premium, I need to get the data as soon as possible. ”

In the conference room, Xu Chuan consulted some questions about the experimental data of ultra-low temperature superconducting copper-carbon-silver composites, 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 down at the desk and continued to ponder.

Since 1911, when H. Kamerin-Onnes discovered that metal elements such as mercury and tin are superconductive, there have been dozens of metal elements that exhibit superconductivity at atmospheric pressure.

There is no unified standard for the classification of superconductor materials.

In general, the most common classification is by temperature.

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

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

In materials science, it is normal to first accidentally get the material, and then find the mechanism by analyzing the material.

Later, when he researched copper-carbon-silver composite materials, he also tried to explore and explain the basis of high-temperature and room-temperature superconducting materials.

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

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

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

When we studied physics in high school, it was easy to learn that each atom had a different number of electrons outside its nucleus.

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

Under normal conditions, the electrons in the solid of these atoms are very stable with each other, and the individual electrons are considered independent and do not affect each other.

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

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

As a result, these materials have a strong correlation effect.

The strong correlation effect between electrons is the reason for many novel physical phenomena.

For example, the fractional quantum Hall effect in two-dimensional electron gases, the giant magnetoresistive effect in manganese oxide materials, heavy fermion systems, and metal-insulator phase transitions in two-dimensional high-mobility materials. Wait a minute.

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

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

And today, Xu Chuan felt that he might be able to give it a try.

Flipping through the experimental data of low-temperature copper-carbon-silver composites researched by Song Wenbai on the computer, Xu Chuan looked at it seriously, ready to start deducing the mechanism of high-temperature superconductivity after being familiar with it.

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

"Academician Xu, the application from the Gucheng Supercomputer Center has fallen, and the time will be five days later, and the Tianhe-1 supercomputer of the Gucheng Supercomputer Center will deploy the computing power you need to simulate and run the mathematical model in your hand."

On the phone, Gao Hongming replied with an application.

Xu Chuan nodded and said, "I know, I'll go over on time." ”

Hanging up the phone, he looked at the data on the computer and picked up the pen on the side of the manuscript paper.

"Five days, you should be able to find some direction, right?"

Xu Chuan muttered to himself softly, without thinking about it anymore, the pen in his hand calculated on the manuscript paper.

"The low-energy physics of the layered structure shown in Figure 1 is mainly determined by the CuO2 plane in it. On the CuO2 plane, the copper atom forms a square lattice, and there is an oxygen atom between the two nearest copper atoms. From the perspective of electronic structure, the electron orbitals involved are mainly the 3d orbital of copper and the 2p orbital of oxygen."

"When the parent material is doped with a certain concentration of holes, it will enter the superconducting phase at low temperatures, 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 Cu 3dx2-y2 orbital, the holes incorporated in the O2p orbital will form a spin monostate bound state with the holes in the Cu 3dx2-y2 orbital, the famous Zhang-Rice monostate."

"The low-energy effective model is established as the t-j model, and the Hamiltonian is calculated as:

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

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

Using mathematics to calculate physics is a breakthrough in his life, and it is also one of his best researches.

Immersed in it, he integrated the ideas in his mind as he calculated the data.

This is a road to explain the mechanism of high-temperature superconductivity, which has been traveled before, but only for a short time, and now, he is moving forward.

Walking on this primitive road, the powerful mathematical ability in this life is the firewood knife in his hand, overcoming thorns and thorns; In his previous life, his physical studies were more like a compass that guided the way and ensured that he would not forge the wrong path.

The perfect combination of mathematics and physics, the last time it was in the field of high-energy physics, the last time it was in the field of high-energy physics, and this time, it is to go deep into the material science to explore the mystery between atoms and electrons.

Little by little, Xu Chuan's eyes only had the pen and paper on the desk, at this moment he seemed to be walking in the dark, his eyes were dark, and only a little lighthouse light flickering in the distance guided him in the direction of his progress.

As the days passed, outside the window, the weather in the middle of winter was unusually heavy rain, 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 shine its light through the clouds and back onto the earth.

In the study, I don't know when I stopped the pen in my hand, stood by the window and looked at Xu Chuan in the distance, looking at the light that fell on the earth through the dark clouds after the rain.

Looking at the sunset slowly setting in the sky, the corners of Xu Chuan's mouth hooked up a smile.

When the Tyndall effect occurs, light takes on a shape.

The light that shines through the sky after the rain is leading the way of civilization.

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

All that's left is to go deeper along this path.

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

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

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

After all, the properties of copper-carbon-silver composite materials developed by him in later generations are somewhat biased towards ceramic materials, although they can achieve superconductivity at room temperature and pressure, they are difficult to process and mold, and are easily disturbed.

This limited room-temperature superconducting material is suitable for controlled nuclear fusion, and the particle collider is a top scientific research equipment, but it is still difficult to widely use it in power generation, transmission, energy storage, weak electricity and other fields.

In particular, those equipment with a relatively harsh working environment cannot be used.

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

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

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

"Academician Xu, you are looking for me."

Xu Chuan nodded, picked up the prepared hard disk and handed it over: "This is a mathematical model for plasma turbulence in the chamber of a controlled nuclear fusion reactor. ”

"Originally, I was going to go to Gucheng to check the calculations in person, but now that the situation has changed, I have some other things in my hands, so I don't plan to go there in person. Please take this hard drive with you. ”

Hearing this, Gao Hongming quickly said: "It's not a matter of running, but if you don't go, I don't understand mathematical models and tests." ”

"If you really can't get out, I'll give you feedback from above? Hold off a bit? That's okay. ”

Xu Chuan thought for a while and said, "Postponement is not the solution. In this case, I will call Academician Peng Hongxi and ask the two persons in charge of the modeling department to come out and accompany you. ”

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

"If there's a problem, you can call me too."

Gao Hongming thought for a while and said, "It's okay, but if you don't go, I'm always a little uncertain in my heart." After all, it's so important. ”

Xu Chuan smiled and said, "If everything goes well, I can't actually do much when I go, just bring back the data after the model verification to me." ”

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

Xu Chuan: "Thank you for your hard work, have a good trip." ”

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

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

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

"Don't worry, the people are here!"

(End of chapter)