Great Country Academician

Hearing such a strange simulation situation, Xu Chuan was also a little surprised.

The phenomenon of superconductivity is sometimes ineffective. Although it is only a simulation test and not the final experimental result, something can be seen.

In particular, the material test of pure data simulation, compared with the results of the replica experiment, it can eliminate some additional interference factors, and it is even purer and more representative to some extent.

"interesting."

Touching his chin and thinking for a while, Xu Chuan muttered to himself, then raised his head and said, "Pack up a copy of the simulation test data of the calculation model and send it to me. I'll take a look."

With his mathematical ability and material ability, he may have the opportunity to find some situations from these data.

But to be honest, for this KL-66 room temperature superconducting material, although he hopes that this is a path that has never been discovered, he does not have much hope.

Regardless of its synthetic route and materials, the name of KL-66 is called "modified lead apatite crystal structure", which is actually lead apatite doped with copper.

Although a high temperature of more than 900 is required to synthesize it, in nature, copper and lead apatite symbiotic ores are not absent, and a high temperature of more than 900 is not difficult.

In the past billions of years of addressing activities, if this material is really superconducting, then there is a high probability that people can find it directly from nature.

But with the development of science and technology, all kinds of minerals on the earth, not to mention all types, have been discovered, at least 99% of the minerals have been identified, but this kind of material has not been found.

Apart from this point, there is another key point that also made him aggravate his unfavorable attitude to a certain extent.

The so-called 'modified lead apatite crystal structure KL-66', according to the two papers on arxiv, the core technology is to use CuCu2+ instead of Pb22+, which induces a small crystal structure distortion, thereby shrinking the volume by 0.48%. In this way, a superconducting quantum well is constructed on the interface of lead ions and phosphate, and this KL-66 material has superconductivity.

But judging from his own years of experience in materials research, this substitution should not be able to form superconductivity.

The first is that lead and copper atoms have extremely similar electronic structures, and replacing some lead atoms with copper atoms should not have a large impact on the electrical properties of the material.

The second is that if he remembers correctly, it is not impossible to use copper atoms instead of lead, but theoretically, the energy required to accomplish this goal is quite high thermodynamically.

The specific amount needs to be calculated, but theoretically speaking, it is definitely not something that can be achieved by burning at 900 degrees for more than ten hours.

After requesting a copy of KL-66 data and calculation model simulation data, Xu Chuan started the calculation in his office.

Although there is no way to conclude that this KL-66 material is not a very temperature superconductor through simple mathematical calculations, it can still be roughly calculated through calculations of the formation energy of atoms, phonon spectra, and tight-binding models.

【E5 = Ef -[(No– 1)/No]* Ei】

[Set variable Cu equal to 3.615, unit metal dimension 3, boundary.]

[Calculate all pe/atoms of the project, calculate the sum of all reductions of the project c_eng]

【Calculate the number of atoms.】

Compared with the core data of the KL-66 paper and some data inferred from the calculation model, Xu Chuan used the software of Chuanhai Materials Research Institute to rewrite the model.

This is one of the cores of computational materials science, and it is not difficult for him.

After spending some time, Xu Chuan put the reprocessed 'package' into the software and started to run it.

After waiting for ten minutes, the running results jumped out.

【Cupb(Cu): △Ef(eV)Max=16.3Mev, △Ef(eV)Min=12.6Mev】

【Cupb(Cu3P): △Ef(eV)Max=16.1Mev, △Ef(eV)Min=12.1Mev】

【Cupb(CuS)1】

Looking at the calculated results, Xu Chuan shook his head.

According to the calculation results of formation energy, in the formation process of KL-66 material, the energy required for copper atoms to replace lead requires a maximum of 16.3 MeV and a minimum of 12.6 MeV.

Even copper sulfide requires a minimum energy level of 8.7MeV.

This result is quite unfavorable for the synthesis of this KL-66 room temperature superconductor.

At a temperature of more than 900, it is completely impossible to heat the molecules inside the material to the order of 10 Mev, which means that it is almost difficult for the copper in the KL-66 material to replace the lead atoms.

According to South Korea, the core technology of KL-66 lies in the use of CuCu2+ instead of Pb22+, which induces a slight crystal structure distortion.

Then from the calculation of the formation energy, the first step was strangled.

Substitution is impossible, let alone crystal structure distortion.

Shaking his head, Xu Chuan did the calculation again, and after confirming that the result was correct, he performed a de novo calculation on the interaction Hamiltonian and phonon spectrum of the KL-66 material.

The calculation results of the phonon spectrum show that there are virtual phonon modes in both the undoped and copper-doped structures of the KL-66 material, indicating that the structure is unstable, which further confirms the calculation results of the formation energy.

As for the interaction Hamiltonian, in the KL-66 material, Cu will form a high-density flat region at the Fermi level. Quantum geometry shows that this region is a strongly localized state, which is not conducive to the formation of superconductivity and is more likely to lead to magnetism.

"Magnetism, it's interesting. Is this thing a strong magnetic material?"

Staring at the calculated result, Xu Chuan thought for a while.

It is not impossible that KL-66 is not a room temperature superconducting material, but a strong magnetic material.

On the contrary, judging from the calculation results of the formation energy, Hamiltonian, and phonon spectrum, it is highly likely that it is a strong magnetic material.

Moreover, strong magnetic materials can also exhibit the characteristics of semi-magnetic levitation in the paper and the video sent by South Korea.

But I have to say that this matter has caused a lot of heated discussions on the Internet.

When Xu Chuan was in class the next day, some students asked about it during the daily questioning session after class.

"Professor, do you know the news about the KL-66 room temperature superconducting material that has been very popular in South Korea recently? Is this true? What do you think?"

Xu Chuan smiled and joked, "Me? Of course I just sat and watched."

Hearing this, the classroom burst into laughter.

Xu Chuan cleared his throat, coughed, and continued, "I do already know about the KL-66 room temperature superconducting material. However, I can't give a definite answer until the replica experiment comes out."

"If it is really a room-temperature superconductor, then for human beings, this is definitely one of the most glorious moments in history. Those who research and invent this material will undoubtedly win the Nobel Prize."

"As a result, materials science will usher in a great change. Its synthesis method will prompt us to focus on the previously neglected and abandoned fields of material synthesis."

"It also means that in the field of materials before, we undoubtedly took a lot of detours. Maybe some materials with extremely high performance can be synthesized in a simpler way."

Hearing this, some students in the classroom immediately asked: "Then professor, do you think it was successful?"

Hearing this question, Xu Chuan thought for a while and said, "If you asked me this question yesterday, I would probably tell you that I don't know. After all, this kind of question generally needs to wait for the results of the replica experiment to come out." to answer."

"But today, I can chat with you."

Hearing this answer, the classroom immediately became full of ears, and many students even prepared their mobile phones and started recording videos.

Xu Chuan saw it, but didn't pay much attention to it, and continued: "After learning about the KL-66 material two days ago, the Chuanhai Materials Research Institute under my name is already conducting replica experiments."

"For the sake of interest, and the calculation of chemical materials is my field of expertise, I did some calculations on some data provided in the papers on arxiv."

"Through the calculation and simulation of the KL-66 material from the formation energy, the Hamiltonian, and the phonon spectrum. From the results, I am more inclined that this material may be a strong magnetic material."

"The first is the calculation of the formation energy. According to the calculation results, an energy of at least 10 Mev is required to replace the lead atoms in the KL-66 material with Cu atoms."

".So on the whole, I am more inclined that it may be a strong magnetic material rather than a room temperature superconducting material."

"Of course, I'm not giving an affirmative answer, it's just some speculation based on the experiments and calculations I've done."

"At present, the Chuanhai Materials Research Institute under my name is already following up the replica experiment in this area. It is expected that the first batch to the third batch of replica KL-66 materials will be released the day after tomorrow, and they will be tested at that time. To verify whether it has superconducting properties."

"About whether KL-66 is a room-temperature superconducting material or something else, everything needs subsequent replication experiments to really answer."

After a slight pause, he continued: "In addition, tomorrow I will sort out the calculation data I did, write it into a paper and post it on Arxiv. If you are interested, you can go and have a look."

"The above is very interesting about some of my original material calculation mathematics."

"I will also open a mathematics course on computational materials later on, which is dedicated to teaching this aspect. Students who are interested can apply for it later."

PS: Ask for a monthly pass for double changes