Chapter 135 Ning Chen, how many papers do you want to publish a year?
"Ning Chen, when did you come back?"
"You came back yesterday, on the flight yesterday morning, and arrived in Shengzhou at noon."
Xu Zhou's thoughts on Ning Ning Chen's professionalism was already familiar. Even if Ning Chen went straight to the laboratory after getting off the plane, Xu Zhou would think it was normal.
"Ning Chen, are you doing experiments at the Chinese Academy of Sciences these days going well?"
"Well, overall it went very smoothly. The equipment of the Chinese Academy of Sciences is indeed very advanced, and it is currently the only place in the country that can complete this experiment."
Xu Zhou looked at the experiments that Ning Chen had done these days. The data also shows that these experimental data are indeed of great significance.
"Yes, it seems that the FeSe film is indeed the key to the entire superconducting system. Ning Chen, I have a hunch that you will soon discover a new superconductor."
"Teacher Xu, I'll lend you some good advice."
After chatting with Xu Zhou for a while, Ning Chen continued to start his experiment.
What Ning Chen wants to do now is to insert a more complex structure into the FeSe film to see if a new superconductor can be synthesized.
According to Ning Chen’s analysis last night, because the interlayer coupling of FeSe is very weak, even if more material structures are added, it is still theoretically possible for materials to achieve superconductivity.
If Ning Chen can follow this idea to synthesize new superconducting materials, then he can further prove the correctness of his theory.
......
In the following time, Ning Chen focused all his energy on this new project.
Ning Chen first tried to add a hydroxide structure based on the original materials.
The initial experiment was naturally not that smooth, but after several failures, Ning Chen gradually found some techniques for synthesizing this substance.
In the previous research on iron-based superconductivity, Ning Chen experienced too many failures, which also gave Ning Chen a very rich experience, and he could quickly adjust the experiment based on feedback from experimental phenomena.
Finally, after constant attempts, Ning Chen synthesized a new substance.
The chemical formula of this substance is (Li-Fe)OHFeSe. If it is tested and found to be a superconductor, it will not only prove Ning Chen’s previous theory, but also continue to expand the scope of iron-based superconductors. family.
With anticipation, Ning Chen came to the testing center to test whether this material was fully conductive.
In previous theoretical calculations, Ning Chen speculated that the superconducting critical temperature of this material is probably within the range of 30K-40K based on the energy gap of this material.
This temperature was far from the vaporization point of liquid nitrogen, so Ning Chen directly chose to use liquid helium as the coolant for the experiment.
After the conductivity measurement experiment started, Ning Chen adjusted the temperature in the test environment while checking the resistance data measured in the instrument.
When the temperature dropped to about 50K, Ning Chen slowed down the cooling rate, because if nothing unexpected happened, it would soon enter the superconducting temperature transition range of this material.
To Ning Chen's delight, as expected, soon after the temperature continued to drop, the resistance of this substance began to decrease sharply.
This degree of change in resistance is not simply due to the effect of temperature on resistance, but because a large number of electrons undergo quantum condensation at low temperatures, and the space motion of electrons outside the nucleus is in a balanced state.
In short, this is a superconducting phenomenon unique to superconductors.
As the temperature decreases, the resistance of this material continues to decrease rapidly.
Finally, when the test environment temperature dropped to about 33K, the resistance value of the material was lower than 10^(-25)Ω.
In other words, this material is indeed a completely conductive material and will most likely be a new superconductor.
Ning Chen tried hard to suppress his excitement and recorded the various experimental data this time.
Although the superconducting critical temperature of 33K is not too high, because this is a superconductor with a new structure, such a discovery is undoubtedly of great significance.
After that, Ning Chen continued to test various other properties of this substance.
Unsurprisingly, this material also satisfies other properties of a superconductor and can be called a superconductor in the strict sense.
Taking these measurement data, Ning Chen found Xu Zhou and told Xu Zhou the news. Xuzhou was also very surprised when he learned the news. It had only been two weeks since Ning Chen started a new project.
"Isn't it? I had a hunch that you would discover a new superconductor, and I didn't expect you to discover it so soon! Ning Chen, how many papers do you want to publish in a year? ?”
Ning Chen is naturally not a person who pursues the number of published papers. If Ning Chen is willing, the number of published papers can be more than double the current number.
"Hey, sometimes, the results will appear by themselves, and I just happened to discover them." Ning Chen joked.
"Okay, okay, don't be angry with me anymore. Seriously, Ning Chen, this superconductor is a brand new iron-based superconductor structure, right?"
"Yes, if according to According to the previous classification of iron-based superconductor structures, this is indeed a completely new structure. Well... let me name it the '11111' structure."
Before this, if we classified the iron-based superconductor structure according to its structure. Superconductors are classified into four structural systems: "1111", "122", "111", and "11".
This new structure discovered by Ning Chen is more complex than all previous iron-based superconducting structures. It has created a new breakthrough in the field of iron-based superconducting research!
Ning Chenxin said that he had to thank Academician Tao Wei for providing him with the opportunity to do experiments at the Chinese Academy of Sciences.
Otherwise, even if Ning Chen could predict theoretically, he would not be able to verify it through experiments.
“Fortunately, the Chinese Academy of Sciences has such equipment. If even the Chinese Academy of Sciences didn’t have it, only foreign countries would have the opportunity to complete this experiment.”
At this time, Ning Chen understood something in his heart. Why do so many top domestic students want to go abroad for further studies, and ultimately stay abroad for development?
Some of the top foreign universities have better platforms and more sophisticated experimental equipment.
This allows them to better display their value and have more opportunities.
But this has undoubtedly created a vicious cycle that will cause more outstanding domestic students to go abroad.
For individuals, this is an understandable choice, but for the country, it is undoubtedly a loss of talent.
Fortunately, over the years, some outstanding scholars who have studied abroad, after making many achievements, are still willing to return to China to help the country with scientific research or talent training.
Even though their return faced huge obstacles, they still made such a decision resolutely.
This made Ning Chen admire them from the bottom of his heart and hoped that one day he could be like them and make his own small contribution to the improvement of the country's scientific and technological strength.
...
In the following experiments, Ning Chen continued to conduct research on this new "11111" iron-based superconducting structure.
During continuous synthesis and testing, Ning Chen discovered that by replacing the Li element with other alkali metal elements such as Na and K, the material can still achieve superconductivity at low temperatures.
Even some non-alkali metal elements, such as Ba, Sr, Ca and other elements, also meet these properties.
With these studies as a basis, Ning Chen continued to revise his previous theories.
Generally speaking, Ning Chen's previous theories were relatively accurate, but there were some minor problems in the details.
In the evening, Ning Chen returned home and continued to analyze these theories in the study.
The improvement of the brainpower index allows Ning Chen to complete very efficient analysis work without frequently resorting to various special states of the system.
After several hours of analysis and calculation, Ning Chen finally got a new formula——
△(k)=-∑Vk,k'·△(k' )/2E(k')tanh(1/2βE(k'))
This formula does not seem very complicated, but it can very well reveal the core mechanism of electron distribution in iron-based superconductors.
Compared with the previous formula, this formula has a wider range of use and higher accuracy. It is of great significance for theoretical calculations in the entire field of iron-based superconductivity.
"Huh... Fortunately, my foundation in mathematics and physics is not bad, otherwise, I would never be able to derive this formula."
During the analysis and calculation process just now, Ning Chen Various mathematical analysis methods, condensed matter physics theory in physics, BCS theory, etc. are used.
Relying on this formula, Ning Chen believes that he will soon synthesize an iron-based superconductor with a higher superconducting critical temperature.
(End of this chapter)