Three hours,

Including the theoretical aspect, as well as the calculation aspect, and even the next experimental part, Fan Zhilong felt that Xu Mang had once again redefined the concept of three-hour time, and it turned out that three hours could do so much content, and even changed a prediction that lasted for more than 80 years.

In this paper, two schemes for obtaining Weyl semimetals are first obtained from the theoretical point of view, one is to break the time inversion and maintain the central inversion symmetry, and the other is to maintain the time inversion symmetry and break the center symmetry inversion.

According to the first type, Xu Mang gives that the materials are pyrochlorite structure, spinel structure, ordinary insulating material, topological insulating material, if according to the second type, Se and Te crystals synthesized under pressure, BiSb and ZrTe provide evidence of the possibility of negative magnetoresistance, and Dirac semimetals.

According to Xu Mang's conclusion, the destruction of the translational symmetry by the magnetic domains brought by the magnetic atoms in the system and the impurity atoms hindered the study of the intrinsic properties of Weyl fermions in experiments, and the preparation of materials is relatively difficult.

Therefore, Xu Mang chose the second method to find a non-magnetic material.

TaAs crystals have become the best choice,

The theory seems to be exactly what it is, but there is too much lack of evidence, that kind of direct evidence, numerical proof.

His second principle calculation has solved all the previous doubts, and it is also a little contrary to the previous theory, this material has no central inversion but maintains the symmetry of time inversion, and can be synthesized naturally, without the need for doping and other delicate and complicated controls.

What's more, there is no complexity such as magnetic domains caused by magnetic materials, and the equipment can be directly used for experimental observation, so as to obtain the most direct evidence.

This...

That's what came out in three hours?!

Xu Mang redefined the concept of time as a three-hour hour.

"Xu Mang?"

"Seriously... How the hell did you do that?" Fan Zhilong asked with a look of disbelief, "What did you do back in your apartment? Fortunately, I have a higher education, and then I think you are God." ”

"Hehe..."

"You're right, I am God, but I understand God's mind from a scientific point of view. Xu Mang said with a smile on his face: "If nothing else, the TaAs crystal is a Weyl semimetal, and the prophecy that has lasted for more than 80 years will be broken." ”

"In my calculations... The lattice constant of TaAs crystal is a=3.44 and c=11.64, presents a body-centered tetragonal structure, belongs to a special group of spatial points, and there are 12 opposite-facing Weyl fermions in the lattice momentum space. ”

"There is an open Fermi arc on the surface, and there are Weyl cones with linear cross-conical band structures that appear in pairs inside. Xu Mang said seriously: "These typical electronic structures can be observed, and I got them directly from the database. ”

Fan Zhilong didn't speak, he kept looking at these contents, and the excitement in his heart was incomparable, if... If all this is true, then a secret that has lasted for more than eighty years is really going to be broken, and this person will be a professor from the Department of Physics at Fudan University.

But...

How to prepare this high-quality TaAs crystal?

"Xu Mang?"

"Huh?"

"Would you make such high-quality TaAs crystals?"

"No!"

Suddenly,

There was silence in the lab, and the two looked at each other, seeing the embarrassment in each other's eyes.

This...

After discussing so much, the head is the way, but the result is that neither of them can prepare this material, which means that the previous theory is all for nothing, even if the theory is correct, no matter how accurate the calculation is, everything is funny without physical objects to do research.

"Hello?"

"Director Liu?" Xu Mang asked cautiously, "Guess who I am?" ”

“...”

There is a scumbag in this kind of speech, and you can know if you think about it with your toes, who else can it be if it's not Xu Mang?

"I have a caller ID!" Liu Guofang, the director of the Department of Materials, asked angrily, "What is the matter with me?" Seems to be in some trouble. ”

"Hey, hey..."

"I just want to ask if our materials department has the ability to prepare TaAs crystals?" Xu Mang asked in a low voice, "A high-quality TaAs crystal." ”

"TaAs crystals?"

"This seems to be something in terms of condensed matter, right?" Liu Guofang said solemnly: "But we should be able to prepare, so what do you suddenly want this material for?"

"Don't ask!"

"To ask is to change the world. Xu Mang smiled and said, "That's okay... If it can be prepared, I will come to your office later, let's discuss it, and prepare high-quality TaAs crystals as soon as possible. ”

hang up

Xu Mang glanced at Fan Zhilong: "It can be prepared, I will go to Director Liu's office in the Department of Materials, and finish this matter, and then use STM equipment to measure the surface electronic state with high precision, and then call it a day!"

"Tomorrow. ”

"See for yourself what time it is. Fan Zhilong reminded.

"Huh?"

"Damn... I'm going to buy groceries, or the tigress at home will have to be fried. Xu Mang put his manuscript in his bag and asked Fan Zhilong, "Professor Fan... You say I'm a big scientist, why am I so humiliated at home?"

“...”

"Who asked you to marry Yang Xiaoman. Fan Zhilong said helplessly: "What kind of woman you marry will pay what price." ”

Price!

is worthy of Professor Fan, who has been in the scientific research community for so long, and hit the nail on the head... Straight to the root of the problem.

Xiao Man is very willful,

But...

Xu Mang sighed, and said with a helpless face: "I'm not afraid of your jokes, I'm good at it." ”

Words fall,

Hurry away.

Following

Xu Mang came to the building of the Department of Materials early, stood at the door of Director Liu for a while, glanced at the fruit basket in his hand, thought carefully and put it at the door, then pushed the door in, and saw Director Liu in the office.

"Director Liu?"

"Busy?" Xu Mang put on his trademark smile, walked up with a shy, and stood opposite Liu Guofang.

“...”

Liu Guofang sighed and said helplessly: "Xu Mang... Your current identity is different, can you show a little seriousness that you deserve?

"It can't be changed. ”

"The nature of the country is easy to change, and it can't be changed... Unless you reincarnate all over again. Xu Mang smiled: "What's that... Can we talk about work first, and then talk about personality?"

"It's rare that you're getting straight to the point for the first time. Liu Guofang asked, "Do you have any relevant information?"

"Yes!"

"Take a look. Xu Mang took out a stack of manuscript paper from his bag and handed it to Director Liu Guofang.

Taking this manuscript paper, Liu Guofang glanced at it, and after a few minutes, he raised his head in surprise and asked solemnly: "You said that the TaAs crystal is the Weyl semi-metal material predicted more than 80 years ago?"

"Yes!"

"Basically true. Xu Mang nodded: "If there is no problem with my calculations, as long as I prepare high-quality TaAs crystals, and then use my modified STM equipment for high-precision measurements, it will be fine!"

Liu Guofang said solemnly: "I'll arrange it immediately!"

Leaving the Materials Building,

Xu Mang's heart returned to calm, and Director Liu Guofang promised to complete the preparation of high-quality TaAs crystals in the fastest time, which is expected to take about three days.

Three days...

That's pretty much it!

Xu Mang calculated the time when the announcement of the June meeting would come out, and it would be released almost a week later, the unilateral resolution of the United States, the so-called global condensation coalition to launch the resolution, and this organization is the only one that lacks China.

Just think about it!

A broken organization is just like the real thing.

Xu Mang was very disgusted with this June meeting, and the most important reason was that he participated in the whole process, and when he saw the so-called technological hegemony of those developed countries, a fire burned in his heart.

This flame is even more ferocious than the last time I saw Xiao Man with sheep ears and wearing a goat's cosplay clothes.

Alas?

Saying...

Xu Mang suddenly had a bold idea, he wanted Xiao Man to go to COS Han Cook, after all, the two are about the same, Yang Xiaoman is the empress of the business world, and Han Cook is known as the Empress of the Pirates, but... Something doesn't feel right.

That's right!

The figure is a fatal shortcoming, Xiao Man... Forget it, it's all tears!

night

Always come quietly,

Xu Mang glanced at Xiao Man, who was scrolling through Weibo next to him, and asked cautiously, "Xiao Man... Humiliation?"

Yang Xiaoman: (* ̄〈 ̄)

Here we go!

This idiot is starting again!

I'm really not afraid to fight, I'm not afraid to scold, why is this stupid guy so iron?

This night,

Xu Mang was humiliated.

...

Institute of Condensed Matter,

On this day,

The research team of Weyl semimetals encountered a dilemma, and according to the theoretical results... They need to make a choice, first of all, between ordinary insulator materials and topological insulator materials, and secondly, between ordinary insulators and topological insulators, and solid solutions that break the symmetry of time inversion or center inversion.

Both materials are possible, but after analysis the second one should be chosen, however... The second type of calculation is too complex to be done.

Professor Tian has been tormented to the point of collapse for this problem, and all kinds of evidence point to the second material, which is a non-magnetic material, but how to choose correctly among many non-magnetic materials requires complex calculations to get the result.

Meantime... Reasonable deduction is also one of the conditions, and without either of these two things it is impossible to complete this step.

ultimately

Professor Tian had to find his friend, a mathematician in China, who wanted to work with him to solve this part of the problem, but the mathematician told him that it would take at least a week.

A week?

It's a week, just a week.

When it came time to solve this problem, the team members were not idle, and they needed to make various assumptions about the experiment so that they could be carried out quickly in the next steps.

"Anyway..."

"Where is Professor Xu?" asked a master's student from the University of Qingdao, "will it be faster than us?"

"Impossible!"

"I have been in contact with my high school classmate, who works as a teaching assistant at Fudan University, and Professor Xu has not had his voice recently, and it seems that the world has evaporated. A graduate student in science said, "Anyway, it can't be faster than us, don't worry... I bet. ”

Then

One girl said, "I think everyone should be mentally prepared, maybe this is the calm before the storm... It is usually peaceful before a storm, but suddenly there is lightning and thunder. ”

All did not speak,

At this moment, they knew they were going to be in a race against time.

......