26: Chapter 26 The discovery of the "Rock" material shocked the academic world.
The preliminary theoretical concept of 'interface-induced high-temperature/room-temperature superconductivity' was like a red-hot pebble cast into a deep pool, stirring up waves within the 'Deep Blue' virtual theory group that were far more intense than Lin Shen had anticipated.
The young professor codenamed 'Tide' was the first to respond, his encrypted message filled with the excitement of enlightenment: "'Guide', this idea of yours is insane! But if it's true, then we aren't just looking for a new material—we're 'designing' a new quantum phenomenon! With the interface acting as an arena for strong correlation and boson modes, the effects of quantum fluctuations and dynamic coupling will be magnified to the extreme! My quantum critical model might be able to describe the 'emergent' order parameters of such low-dimensional interface systems after some modification! I'm starting to adjust the model parameters immediately!"
The computational materials expert codenamed 'Weaver' showed extreme pragmatism and caution: "The theoretical framework is highly inspiring, but the computational challenges increase exponentially. Simulating the bulk properties of two independent materials is difficult enough; calculating the electronic structure, phonon spectra, and the coupling matrix between them at the interface with high precision requires immense computing power. Not to mention the need to consider real-world factors like interface roughness, defects, and interdiffusion. However, if we concentrate our efforts on high-throughput screening of a few theoretically promising 'material pairs' first—for instance, a copper oxide analog with strong electronic correlation paired with a perovskite oxide possessing strong polarity or special optical phonons—we might quickly eliminate the most implausible combinations and find a few 'candidates'. I need to reconfigure the algorithms to prioritize interface electron-phonon coupling calculations for these types of heterojunctions."
The astrophysicist codenamed 'Stardust' sent a long commentary filled with mathematical symbols: "An interesting perspective. Transforming extreme conditions that cannot be replicated on an astrophysical scale into controllable 'extreme' coupling at an artificial interface. This reminds me of certain theories regarding 'dynamic gauge fields'... Perhaps the competition and intertwining of two different quantum orders at the interface could simulate an equivalent 'pseudo-gauge field', thereby inducing unconventional Bose condensation. I can try to formalize this idea and provide a more rigorous field theory framework to describe the 'driving' effect in your model."
Lu Yunshan ('Topologist') provided the calmest and most constructive feedback: "The 'Guide's' model points out the criticality of interface coupling. From a topological perspective, this artificial heterojunction interface itself could define a new 'synthetic space' with non-trivial topological properties. If the superconducting order parameter possesses topological protection within this synthetic space, its stability might be stronger than that of traditional bulk superconductivity, potentially allowing for higher temperatures. I can try to extend your simplified model into a framework containing more orbital and spin degrees of freedom and calculate its possible topological invariants to see if we can find a theoretical 'robustness' criterion."
The feedback, supplements, and even challenges from the members based on their respective fields of expertise rapidly pushed Lin Shen's rough 'thought experiment' model into a deeper and more complex stage of theoretical exploration. New, more refined, and more ambitious computational tasks were constantly proposed and added to the 'heart of deep blue's' queue. The demand for computing power soared, but the enthusiasm for exploration and the sense of direction were clearer than ever before.
Lin Shen played the role of coordinator and integrator, constantly organizing the theoretical clues from different directions and weaving them into a more coherent and persuasive draft report titled 'Demonstration of the Possibility of Interface-Induced High-Temperature Superconductivity'. He deliberately emphasized the 'unconventional' nature of this approach, the extreme challenges it posed to material synthesis and characterization techniques, and its current status as a preliminary exploration of 'theoretical possibilities' to avoid raising unrealistic expectations.
While the 'Deep Blue' project was performing high-risk leaps in the theoretical clouds, a heavy piece of news—unexpected yet within the realm of reason—arrived on the ground of the real world. This news did not come from the 'Deep Blue' group, and it was temporarily unrelated to controllable nuclear fusion, yet it acted like a shot of adrenaline injected into the domestic tech industry, which had been somewhat stifled by the energy crisis and multiple blockades.
The news came from a private achievement release conference held by the National Association of Materials Science. A top domestic university's School of Materials, in collaboration with several research institutes, announced a breakthrough in the field of superconducting materials after eight years of joint research!
They successfully synthesized and characterized a brand-new superconducting material system based on the interface engineering of single-layer Iron Selenide (FeSe) films and special oxide substrates. Using Molecular Beam Epitaxy (MBE) technology, they grew atomically flat single-layer FeSe films on specific Strontium Titanate (SrTiO₃) substrates, achieving ultimate control over the film's electronic structure by utilizing the biaxial tensile strain and interface charge transfer provided by the substrate.
The experimental results were shocking: the superconducting transition temperature (Tc) of this single-layer FeSe/STO heterojunction reached a staggering 65K (minus 208 degrees Celsius)! Although still far from room temperature, it had already surpassed the critical temperature of the vast majority of copper oxide high-temperature superconductors, becoming the superconductor with the highest critical temperature under non-copper-based and non-high-pressure conditions!
More importantly, through precise Angle-Resolved Photoemission Spectroscopy (ARPES) and Scanning Tunneling Microscopy (STM) measurements combined with theoretical calculations, the team clearly revealed for the first time that the origin of this high-temperature superconductivity was closely related to the enhanced electron-phonon coupling at the interface and possible interface phonon modes! This provided an extremely valuable experimental sample for understanding the mechanism of high-temperature superconductivity and directly validated the extreme importance of 'interface engineering' in raising superconducting temperatures!
This achievement was named the 'bedrock-1' material system. The name symbolized its experimental data, as solid as a rock, and its role as a new cornerstone for future superconducting material research.
Although the news was initially released within a limited scope, the core data of '65K interface superconductivity' was too dazzling. It quickly caused an earthquake-like reaction in the condensed matter physics and materials science communities both domestically and internationally through informal channels!
Editors of major international academic journals moved upon hearing the news, and heads of top laboratories began urgently reviewing relevant preprints (not yet officially published). Many teams conducting similar interface superconductivity research felt both invigorated and under immense pressure.
The 'Starry Sea' knowledge base immediately indexed the complete experimental reports, raw data, and analytical papers (preprint versions). Inside the 'Firmament' base, Lin Shen read through all the materials, almost holding his breath.
Shocking!
It wasn't just because of the number 65K, but because the success of the 'bedrock-1' system provided a real-world, powerful footnote and example for the insane concept of 'interface-induced high-temperature superconductivity' in his mind, using irrefutable experimental data!
The Tc of bulk FeSe material is only around 8K. But by thinning it to a single layer and placing it on a specific STO substrate, and utilizing interface strain and charge doping, the Tc was increased by more than eight times! Its core physics was confirmed to be related to the strong coupling between the special phonon modes at the interface (the optical phonons of the STO substrate) and the electrons in the FeSe layer.
Wasn't this exactly the 'interface superconductivity' envisioned by the 'Deep Blue' group, where 'Material A (strong correlation layer? FeSe isn't typically strong correlation here, but has rich electronic states) and Material B (special boson layer, STO providing interface phonons)' induce performance far exceeding that of bulk materials through interface coupling?
Although 'bedrock-1' was still far from room temperature, it clearly signaled a path: through atomically precise design and control of heterojunction interfaces, one could greatly alter or even create new superconducting states and significantly increase their critical temperatures.
This was not just a material breakthrough, but a paradigm shift! It told the world that superconducting research could not just focus on the chemical formulas of bulk materials; it also had to pay attention to the 'surfaces' and 'interfaces' where materials meet—where unexpected physics and performance leaps might be hidden.
The emergence of 'bedrock-1' was like a powerful searchlight piercing through the fog, not only illuminating a key direction for high-temperature superconductivity research but also indirectly providing valuable 'real-world rationality' support and experimental methodology for Lin Shen's secret and more extreme 'Deep Blue' exploration.
He immediately packaged all the data on 'bedrock-1' and distributed it to every member of the 'Deep Blue' virtual theory group as an important reference case.
"Look! Our direction might really be right!" Lin Shen could hardly hide his excitement in the group's encrypted channel. "'bedrock-1' proves the enormous potential of interface engineering. What we need to do now is follow this illuminated path and continue our theoretical exploration and material design toward more extreme and unknown 'high-temperature' and even 'room-temperature' regions! 'Weaver', please immediately include material pairs similar to FeSe/STO and others with strong interface coupling potential into our priority screening range! 'Tide', 'Stardust', and 'Topologist', please refine and deepen our theoretical models based on the experimental details of 'bedrock-1' to find the theoretical levers for further increasing Tc!"
The members were equally encouraged. The appearance of 'bedrock-1' caused their seemingly wild theoretical ideas to instantly connect with the most cutting-edge experimental progress, no longer making them pure castles in the air.
While the 'Deep Blue' group was invigorated and stepped up their deductions, the shockwaves of 'bedrock-1' also rapidly spread to broader fields, triggering complex chain reactions.
First, naturally, was the shock and follow-up from the international academic community. Several top international laboratories announced they would launch or strengthen research into similar interface superconductivity. The number of paper citations and preprint submissions in related fields exploded.
But at the same time, pressure and vigilance from the outside world also suddenly escalated. Relevant Federal departments and think tanks quickly issued reports, acknowledging the advanced nature of the 'bedrock-1' achievement while emphasizing its 'potential strategic significance', implying a need to strengthen control over related technologies (such as atomic-level film growth and interface characterization) and beginning discussions on whether to include certain special substrate materials and precision MBE equipment components used in such research on export control lists.
Director Zhao of the Energy Security Committee sent Lin Shen a brief but meaningful instruction: "The light of 'Bedrock' is worth celebrating; it illuminates the path ahead, but it also draws the wolves. What you of 'Deep Blue' seek is grand and far-reaching; you should take advantage of this momentum to further sharpen your blade, but you must also remain hidden deep underground, waiting for the thunder."
The meaning was: the result is excellent and proves the direction, but it has also attracted greedier attention. The 'Deep Blue' project has a larger goal and should use this opportunity to accelerate, but it must also be more covert, waiting for the moment of true eruption.
Lin Shen deeply agreed. 'bedrock-1' brought not only inspiration and cover but also the possibility that the 'Deep Blue' project itself would face stricter scrutiny and more intense competition if discoveries were made in the future.
He replied to Director Zhao: "Understood. 'Deep Blue' will continue to move silently; the blade of theory only waits for the data to sharpen its edge."
Putting down the communication, Lin Shen looked at the eternally flowing plateau starry sky on the simulated exterior screen. 'Bedrock' had emerged, shocking the academic world and stirring up the winds of change.
And for those explorers under the 'Firmament' trying to knock on the door of 'room temperature', could the theoretical hammer in their hands strike that final and loudest echo upon the foundation laid by 'Bedrock'?
The road was still beneath their feet, stretching through the complex data and formulas toward that light which seemed unreachable, yet appeared a bit closer because of 'Bedrock'.