For everyone is not optimistic about graphene, Xu Mang feels that it is understandable, although many people believe that graphene may achieve room temperature superconductivity, and there are many theoretical data on this, all of which support this statement.

But...

Judging from the graphene superconductivity experiment of the foot basin chicken, it is almost impossible for graphene to become a superconducting material at room temperature, and the concept of minus 269 degrees has completely destroyed the practical value, and this experiment only shows that graphene has superconducting properties.

The challenge Xu Mang is now facing is how to obtain superconducting performance in different ways.

"What's wrong?"

"Look at the way you look upset. Yang Xiaoman, who had eaten dinner, was really lying in Xu Mang's arms, and had just finished reading a Weibo, but he saw Xu Mang's sad face, and asked curiously: "Are you worried that the cow that was blown out will fall down and be stoned to death?"

"It's not. ”

"I'm thinking about the sandwich-style double-layer graphene compound for footbasin chicken. Xu Mang said: "Inserting calcium atoms between the double-layer carbon atom graphene films actually achieves superconductivity, although it needs to be minus 269 degrees Celsius. ”

"What's the name of this compound?" asked Xu Mang.

“C6CaC6！”

"Yes, yes, yes!" Xu Mang nodded: "Is it the relationship between calcium atoms?"

Yang Xiaoman said seriously: "I said that you are a big fool, you only read half of the paper? The latter research team inserted lithium to replace calcium between the double layers of graphene, and the result was that the lithium interlayer compounds did not have superconductivity. ”

"Huh?"

"Could it be caused by calcium atoms donating electrons to the graphene layer?" Xu asked in surprise.

Xiao Man shook his head: "How do I know... Why don't you go back to the lab now and test the data to test your hypothesis?"

"Good..."

"What a ball!" Xu Mang's words reached his mouth, noticed Xiao Man's expression, and hurriedly changed his words: "I don't hold such a beautiful girlfriend at home, and I run to the empty laboratory alone, I have a brain disease?"

Words fall,

Xiao Man was satisfied.

"I think... Finding out the physical properties of superconducting graphene and its theory is what we need to do at present. After a day of training, Yang Xiaoman has accumulated a lot of knowledge in this area, and Chong Xu Mang said: "We can make metal compounds, or try to change the graphene layer, miracles may happen." ”

Change the number of layers?

Yang Xiaoman's words provided Xu Mang with different ideas, of course, all this needs to be clarified in order to understand the properties of superconductivity.

night

Quietly coming.

In a similar situation as yesterday, Yang Xiaoman had an inexplicable irritability, and Xu Mang felt... When the time continues to decrease, every night that passes, Yang Xiaoman's irritability index will rise a little, so it is estimated that by the night of the Chinese New Year's Eve, Xiaoman will explode in place.

"Huh?"

"What's your situation?" Xu Mang looked at Xiao Man in his arms with a happy face, and suddenly had a headache, and said, "Are you looking forward to it so much?"

"You care about me!"

"Big idiot... Did you have a girlfriend before?" Yang Xiaoman squeaked and whimpered, "How many are there?"

Wait a minute!

Routines, traps, traps!

Deliberately dug a big pit to make yourself jump.

Cut!

"Nope!"

"I'm a very pure person, except for you leaning on me, I don't usually talk to girls. Xu Mang said seriously.

Hearing Xu Mang's words, Yang Xiaoman was very angry, what is the meaning of leaning on you? Who was making a fuss behind you in the first place? Who kept making small movements? Isn't this just to attract the attention of the old lady.

"Oops..."

"What do you say!" Yang Xiaoman urged: "I won't be angry. ”

Won't be angry?

Hehe...

How many girls say to their boyfriends that they won't be angry, but the boy says it, and after he finishes speaking, he gets angry.

"Not really!"

"I really only have one girlfriend for you, and I used to be alone... Do you think to yourself, when I was in school, who would want to make friends with me?" Xu Mang sighed: "After all, I'm so handsome, they will be under pressure." ”

Oops!

I want to kill him!

Yang Xiaoman originally wanted to beat him up and come up with an invincible reason, but this reason inadvertently became a stepping stone for him.

"Handsome!"

"Handsome fart!" Yang Xiaoman glanced at him: "Carry me upstairs, I'm going to sleep!"

Fortunately, Xiao Man was very light, and Xu Mang carried her up the stairs in the form of a princess hug.

The voice is very soft,

The action is small,

But it's better to die than to die... Mother Xu opened the door and saw this scene, her son hugged her daughter-in-law, sneaky look, and then looked at the expressions of the two, her son was full of nervousness, and the daughter-in-law buried her head in her arms, looking at it from the side... It's red!

"Ahem!"

"Be careful at night. ”

Words fall,

Mother Xu walked down the stairs and went to the kitchen without knowing what to do.

“...”

“...”

The two of them are called embarrassed.

"Ink what?"

"Are you going to wait for your mother to come up and say another word?" Yang Xiaoman raised his head and glared at Xu Mang: "Hurry up and open the door!"

hastily

Xu Mang and Xiao Man came to the room and locked the door with their backhands.

This night,

It's still so tormenting.

...

Following

Back to the lab.

Xu Mang began the next experiment.

With the help of the quantum database, the superconductivity problem of C6CaC6 was roughly figured out, and it was indeed caused by the calcium atom providing electrons to the graphene layer.

"What's wrong?"

"What problems did you encounter?" Yang Xiaoman saw Xu Mang frowning, got up to help him rub the corners of his eyes, and said, "Long-term frowning will cause crow's feet." ”

"I think..."

"You said that this graphene is a hexagonal flat film composed of carbon atoms in a honeycomb lattice, with a thickness of only one carbon atom in a two-dimensional material, but superconductivity can be achieved with calcium atoms in the middle?" ”

“...”

"I don't know. Yang Xiaoman said: "But you can know... There are many ways in which graphene can be superconducted. ”

"What do you think I should do now?" asked Xu Mang.

"We have to look for answers from other high-temperature superconductors," Yang Xiaoman said, "Observe the superconducting properties of other superconductors and the changes in the quantum microscopic world." ”

“...”

Alas?

Wait a minute!

Xu Mang suddenly realized, as if he had forgotten a certain step, it may be this key step!

strong interaction between electrons,

That is, the highly entangled state caused by mutual repulsion between electrons, in all high-temperature superconductors, shows strong interaction between electrons, which is the key to achieving superconductivity.

Followed by

Yang Xiaoman found a paper from a previous physicist, which, although prophetic, provided a direction for the two men's work, saying that when the angle of rotation of the bilayer of graphene changes, there may be an electronic interaction.

"Stupid. ”

"If the two layers of hexagonal graphene with a honeycomb lattice rotate at an angle, doesn't it just produce a kind of ripple like a flickering effect?" Yang Xiaoman pointed to the display screen: "Look, is this moiré?"

"Nonsense!"

"This is an inevitable effect when two geometrically regular patterns overlap. ”

As soon as the words fell,

Xu Mang reacted at this time.

The rotation of the angle produces not only moiré patterns, but also extended cells.

afterwards

Through the design of the model, Xu Mang found that when the rotation angle of the two layers of graphene changes, the ripples between light and dark can be seen very clearly, and the smallest repeating unit of the ripple is the shape of a diamond.

Not only that,

Xu Mang also found another strange feature, AA in the bright part, AB or BA in the darker part, so the layout... It doesn't happen to form the concept of crests and troughs.

"Xiao Man!"

"Is there a relevant calculation equation on that prophetic paper?" Xu Mang asked.

"I'll see..."

"Yes!" Yang Xiaoman said.

"Give it to me. ”

"Oh..."

Xu Mang got the printed paper and checked it again and again, especially about the calculation part, according to the calculation results of this paper, when the two layers of graphene are rotated, the Fermi velocity may be changed.

But...

Xu Mang felt that there was a problem with the calculation.

It seems to be wrong.

Because according to the above calculation results, it is impossible to make the Dirac cone of two-dimensional graphene produce an energy gap, so that its Fermi velocity can be readjusted.

"Holy!"

"It was a beautiful mistake. Xu Mang let out a long sigh and said to Xiao Man: "Xiao Man... The next two days are likely to be stressful. ”

"Huh?"

"Why?" Yang Xiaoman pouted and said unhappily: "I came to Ning City to enjoy it, and now I feel... Become your toolman. ”

Xu Mang smiled and said: "It's you who want to come, and you can't persuade you, so what can you do, forget it... I'll go alone, because it all involves quantum mechanical calculations, and you may not understand it. ”

"Phew!"

"Why can't you understand?" Yang Xiaoman was unconvinced: "What is it?"

"Dirac's equation for quantum mechanics. Xu Mang smiled and asked, "This is a quantum mechanical equation about the relativism of electrons. ”

“...”

Listening to Xu Mang's explanation, Yang Xiaoman's face was full of confusion at this time, what is this and what.

Xu Mang thought for a while, and said to Xiaoman: "Really... You can rest tomorrow, I can do it alone. ”

"Don't!"

"I'm going to be with you. Yang Xiaoman said stubbornly: "Don't try to drive me away, otherwise I will kill you!"

Xu Mang:( ̄△ ̄;)

ultimately

Yang Xiaoman still stayed by Xu Mang's side and became a tool man.

Of course... She didn't have to do anything.

Be a mascot,

Decoration

Vase.

In the time that followed, Yang Xiaoman watched Xu Mang constantly calculating, writing one equation after another, but he couldn't understand these equations, and he didn't even know the meaning of every symbol on them.

"What is this?"

"The energy gap equation. ”

"And what is this?"

"The solution of Dirac's electronic positive energy unfolds. ”

“...”

Yang Xiaoman was silent.

After feeling Xiao Man's emotional changes, Xu Mang put down the pen in his hand and asked with a smile, "What's wrong?"

"I felt like an idiot. Yang Xiaoman pouted and said helplessly: "What you wrote... I don't even understand, when we first met, you were stupid, and now..."

Xu Mang patted his thigh and said with a smile: "Sit up yourself, and I will teach you the relativistic quantum mechanical equations of electronic motion in quantum mechanics." ”

Just a few minutes after sitting down, Yang Xiaoman was wrapped in happiness, and the door of the laboratory was opened.

"Ahem!"

......