He, Song Wenbo, and Gong Zheng each led a team, selected different directions for research, and collected experimental data.

On December 24th, the day before Christmas, the weather in the late winter was unusually heavy rainy and the sky was covered with dark clouds.

In the laboratory of the Chuanhai Institute of Materials, Xu Chuan, wearing a white coat, protective mask and goggles, fed the material in his hand into the electron beam evaporation coating machine.

Since it has been decided to complete the research and development of room temperature superconducting materials before Gu Bing gets married, it is necessary to leave a few days for preliminary verification.

Christmas Eve was a good day. According to the process in his memory, Xu Chuan had already started the synthesis of copper oxide-based chromium-silver system room-temperature superconducting materials.

For him, even if it has been more than ten years since he synthesized copper peroxide-based chromium-silver superconducting materials by himself, it is impossible to forget the entire synthesis process.

In fact, the core key to room temperature superconductors does not lie in studying the ‘doping’ methods of other superconducting materials.

But it lies in another direction.

That is, localized electron delocalization, which is the so-called condensed matter electron localization structure.

In fact, in the history of human research on superconducting materials, doping can be said to be the most important method.

Taking conductivity as an example, it is mainly determined by carrier concentration and mobility.

Experience gained from the development of semiconductor chips, elemental silicon, etc., to increase the carrier concentration requires doping, gate voltage injection, light injection, etc.

However, doping will inevitably lead to an increase in impurities and defects and a decrease in mobility, so it is necessary to consider the balance and compromise between the two.

Searching for a superconducting material whose structure and energy levels match that of N-type doped phosphorus and silicon in semiconductors is something that almost all scholars in the field are doing.

Most superconducting materials were discovered in this way.

Appropriate doping will increase the critical temperature and critical current intensity of superconducting materials.

Whether it is low-temperature/high-temperature superconducting materials, whether it is copper oxide, or iron-based superconducting materials, these properties are improved by doping these basic materials with other elements during the research and development process.

However, people do not know which dopant in superconducting materials can achieve such a perfect fit as the 'silicon doped with phosphorus' of semiconductors.

Therefore, the research approach to superconducting materials is exhaustive.

If you try the elements in the rows on the periodic table one by one, there will always be one or a few that can achieve the optimal match of structure and energy level.

However, materials science is a very complex field, the material world is also so complex, and dopants are far more than just elements.

Just like the A position of perovskite ABX3 has changed from the original atom to a more complex methylamine group, the idea is opened immediately, and the complexity is certainly opened up.

At this time, purely relying on the parameter scanning of the exhaustive method and stacking manpower and material resources on research ideas will obviously be insufficient in the face of infinite number of compound groups.

Perhaps AI and big data calculations will be a good solution in the future.

But condensed matter physics and strongly correlated electronic systems told Xu Chuan that there is actually another way here.

That is the localized electron delocalization of the material!

That is to say, try to keep localized electrons as close to the Fermi surface as possible instead of being buried deeply in the inner layers of atoms.

As long as the electrons of the material can be stably brought near the Fermi surface, the current can be guided to the greatest extent.

How to build such a system is the real key to realizing room temperature superconducting materials.

As for the synthesis method, based on current technology, there is no doubt that it is nano-synthesis technology.

Only extremely fine nanomaterial synthesis technology can accurately control every area of ​​the material surface.

Copper oxide-based chromium-silver room temperature superconducting materials are synthesized through nanotechnology.

Under specific conditions, by fine-tuning the stacking and twisting of the surface of the copper oxide crystal layer, and then incorporating silver and chromium elements, the maximum supercurrent at the interface can be changed according to the direction of the current, and electronic control of the quantum state of the interface can be achieved.

The polarity of the current is changed to change the quantum state, thereby achieving superconductivity.

Unfortunately, it is still not a room temperature superconducting material in the 'narrow sense' and requires a certain external pressure to stabilize the electron delocalization of the Fermi surface.
Chapter completed!