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

The phenomenon of superconductivity does not work from time to time, although it is only a simulation test, not the final experimental result, but some things can be seen.

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

"It's kind of interesting."

Touching his chin and thinking for a while, Xu Chuan looked up after muttering to himself: "Package a copy of the simulation test data of the calculation model as a whole and send it to me, I'll take a look." ”

With his mathematical abilities and material prowess, there may be a chance to find some information from this data.

But to be honest, he didn't have much hope for this KL-66 room-temperature superconducting material, although he hoped that it was a path that had never been discovered.

Aside from its synthesis route and materials, the name of KL-66 is 'modified lead apatite crystal structure', which is actually lead apatite doped with copper.

Although it takes more than 900 high temperatures to synthesize, in nature, copper and lead apatite symbiotic ore is not nothing, and more than 900 high temperatures are not a difficult thing.

In the past billions of years, if this material is really superconductive, then it is likely that people can find it directly from nature.

However, with the development of science and technology until now, all kinds of minerals on the earth, not to mention all types, have been discovered, at least more than 99% of the minerals have been discovered, but this material has not been discovered.

Aside from this, there is another key point that also makes him aggravate his not very optimistic attitude to a certain extent.

According to the so-called 'modified lead apatite crystal structure KL-66', according to the two papers on arxiv, the core technology lies in the use of CuCu2+ instead of Pb22+, which induces a small distortion of the crystal structure, thereby shrinking the volume by 0.48%, so as to construct a superconducting quantum well at the interface between lead ions and phosphate, and make this KL-66 material superconductive.

However, based on his own years of experience in materials science, 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, the use of copper atoms to replace lead is not impossible, but theoretically the energy required to accomplish this goal is thermodynamically quite high.

The exact amount still needs to be calculated, but theoretically speaking, it is definitely not something that can be done by burning at a temperature of 900 degrees for more than ten hours.

Asked for a copy of the KL-66 data and the simulation data of the calculation model, Xu Chuan carried out the calculations in his office.

Although there is no way to conclude that this KL-66 material is a non-thermal superconductor through simple mathematical calculations, it can still be roughly deduced by calculating the formation energy of atoms, phonon spectrum, and tightly bound model.

【E5 = Ef -[(No– 1)/No]* Ei】

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

[Sum of all PE/ATOM in the calculation process and c_eng in the reduction of the calculation process]

Calculate the number of atoms. 】

According to the core data of the KL-66 paper and some of the data inferred from the calculation model, Xu Chuan used the software of the 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 began to run.

After waiting for about 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 results of the calculation, Xu Chuan shook his head.

According to the results of the formation energy calculation, the energy required for copper atoms to replace lead in the formation process of KL-66 material is 16.3 Mev at the highest and 12.6 MeV at the lowest.

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

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

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

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

Then, judging from the calculation of the formation energy, the first step is to strangle.

Substitution can't be done, let alone distortion of the crystal structure.

Shaking his head, Xu Chuan did the calculation again, and after confirming that the results were correct, he calculated the interaction Hamiltonian and phonon spectrum of the KL-66 material from scratch.

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

In the case of KL-66 materials, Cu forms 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 kind of interesting, is this thing a strong magnetic material?"

Staring at the calculated results, Xu Chuan thought for a moment.

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

On the contrary, from the calculation results of the formation energy, Hamiltonian and phonon spectrum, the probability that it is a strong magnetic material is quite high.

In addition, the strong magnetic material can also exhibit the characteristics of semi-magnetic levitation in the paper and the video posted by South Korea.

However, 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 this matter in the daily question session after class.

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

Xu Chuan smiled and teased, "Me? I sat and watched, of course. ”

Hearing this, the classroom burst into laughter.

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

"If it really is a room-temperature superconductor, then it will definitely be one of the most glorious moments in history for mankind, and the person who researched and invented this material will undoubtedly win the Nobel Prize."

"And materials science will also usher in a great change. The way it is synthesized will prompt us to look at the field of material synthesis that has been neglected and abandoned before. ”

"It also means that in the previous field of materials, we have undoubtedly taken a lot of detours. Perhaps some materials with extremely high properties can be synthesized in a simpler way. ”

Hearing this, a student in the classroom immediately asked, "Professor, do you think it has succeeded?" ”

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 either." After all, this kind of question can only be answered after the results of the replication experiment come out. ”

"But I can talk to you today."

Hearing this answer, the classroom suddenly became ear-stricken, and even many students prepared their mobile phones and began to record videos.

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

"And for the sake of interest, and because chemical material calculations are my area of expertise, I did some calculations on some of the data presented in the paper on Arxiv."

"The KL-66 material was calculated and simulated from the formation energy, Hamiltonian and phonon spectrum. Judging by the results, I am more inclined that this material may be a strong magnetic material. ”

"The first is the calculation of the formation energy, from which it appears that the Cu atom needs at least 10 Mev or more energy to replace the lead atom in the KL-66 material."

So overall, I'm more inclined to think that it might be a strong magnetic material, rather than a room-temperature superconducting material."

"Of course, I'm not answering in the affirmative, just some speculation based on the experiments and calculations I've done."

"At present, the Chuanhai Institute of Materials under my name has been following up on the replication experiment in this regard, and it is expected that the first to third batches of replica KL-66 materials will come out the day after tomorrow, and it will be tested at that time to verify whether it has superconducting properties."

"As for whether KL-66 is a room-temperature superconducting material or something else, everything needs to be reproduced in subsequent experiments to truly answer."

After a slight pause, he continued: "In addition, tomorrow I will sort out the calculation data I have done, compile it into a paper and send it to Arxiv, if there are interested students, you can go and take a look." ”

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

"I will also open a mathematics course on computational materials science in the future, specializing in teaching this kind of things, interested students, you can apply for it later."

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