Berkeley Supercomputer Modeling and Chinese Experimental Research Says LK99 Variant Superconductors are BACK!

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Sinéad Griffin, a theoretical physicist at the Lawrence Berkeley National Laboratory, and other experimentalists at Lawrence Berkeley National Lab have reviewed the work from Chinese labs working on room temperature and near room temperature superconductors. The evidence is not yet conclusive but her intuition is that the room superconductivity claims will pan out. The Chinese labs and the Korean Labs are both working on LK99 variants with sulfur blocking chemical points to ensure the copper substitutes at the right location.

Her supercomputer modeling (two research papers), the Chinese experimental research says LK99 variant is back as a superconductor. This is a stronger statement than she made in August 2023 when she wrote her first theoretical paper that computer simulations and models were showing that LK99 could work if the copper were in the right spots. Her newest paper shows one dimensional superconductivity could work and the models suggests improvement to the chemical formulation.

Seokbae Lee, CEO of Quantum Energy Research Institute, who claims to have created the room temperature and pressure superconductor ‘LK-99’, said, “The material PCPOSOS developed is a superconductor.”

Chinese researchers have precisely created very similar material as the original korean team. Nine other groups in China are also working on replications and improvements. China researchers have found microwave and magnetic readings consistent with Meissner effects and superconductivity at about -20 celsius. The effects could start at room temperature, but the evidence is stronger at -20. The readings are weak but they are improving the materials.

These are the statements by Sinéad Griffin from an interview given to New York magazine.

“It’s [chinese research] a really interesting result,” says Sinéad Griffin, a theoretical physicist at the Lawrence Berkeley National Laboratory. “It seems to be two independent teams that came together and had similar results. My experimental friends say their work is good quality. The one thing is that it needs to go through peer review and to be replicated.”

Asked what her gut feeling is about whether the superconductivity claims will pan out, Griffin responds: “I almost sound like a crazy person when I answer this, but I think it is a superconductor. I just say that it’s very, very hard to synthesize.”

Sinéad Griffin has worked with other theoretical researchers to use supercomputers to model LK99 and other materials in the category of LK99.

In July, 2023, Sinéad Griffin, Berkeley Lab researcher, published the simulation of LK99 paper. The paper did *not* prove nor give evidence of superconductivity in Cu-apatite. It showed interesting structural and electronic properties that have features common with high-Tc superconductors provided Cu is in the right place.

Dec, 2023 paper with Sinéad Griffin. Edge-sharing quasi-one-dimensional cuprate fragments in optimally substituted Cu/Pb apatite. AKA One dimensional superconductivity looks hood for copper substituted lead apatite.

The flurry of theoretical and experimental studies following the report of room-temperature superconductivity at ambient pressure in Cu-substituted lead apatite CuxPb10−x(PO4)6O (`LK99′) have explored whether and how this system might host strongly correlated physics including superconductivity. While first-principles calculations at low doping (x≈1) have indicated a Cu-d9 configuration coordinated with oxygen giving rise to isolated, correlated bands, its other structural, electronic, and magnetic properties diverge significantly from those of other known cuprate systems. Here we find that higher densities of ordered Cu substitutions can result in the formation of contiguous edge-sharing Cu-O chains, akin to those found in some members of the cuprate superconductor family. Interestingly, while such quasi-one-dimensional edge-sharing chains are typically ferromagnetically coupled along the chain, we find an antiferromagnetic ground-state magnetic order for our cuprate fragments which is in proximity to a ferromagnetic quantum critical point. This is a result of the elongated Cu-Cu distance in Cu-substituted apatite that leads to larger Cu-O-Cu angles supporting antiferromagnetism, which we demonstrate to be controllable by strain. Finally, our electronic structure calculations confirm the low-dimensional nature of the system and show that the bandwidth is driven by the Cu-O plaquette connectivity, resulting in an intermediate correlated regime.

Another Dec, 2023 paper with with Sinéad Griffin. Electron-phonon coupling in copper-substituted lead phosphate apatite. LK99 would not work if it depended upon electron-phonon interaction, but this does not rule out other mechanisms.

Recent reports of room-temperature, ambient pressure superconductivity in copper-substituted lead phosphate apatite, commonly referred to as LK99, have prompted numerous theoretical and experimental studies into its properties. As the electron-phonon interaction is a common mechanism for superconductivity, the electron-phonon coupling strength is an important quantity to compute for LK99. In this work, we compare the electron-phonon coupling strength among the proposed compositions of LK99. The results of our study are in alignment with the conclusion that LK99 is not a likely candidate for room-temperature superconductivity if electron-phonon interaction is to serve as the mechanism.

The Chinese work placing sulfur in the wrong places ensures that copper (Cu) get substituted in the right palce when a substitution occurs.

1. Possible Meissner effect near room temperature in copper-substituted lead apatite

With copper-substituted lead apatite below room temperature, we observe diamagnetic dc magnetization under magnetic field of 25 Oe with remarkable bifurcation between zero-field-cooling and field-cooling measurements, and under 200 Oe it changes to be paramagnetism. A glassy memory effect is found during cooling. Typical hysteresis loops for superconductors are detected below 250 K, along with an asymmetry between forward and backward sweep of magnetic field. Our experiment suggests at room temperature the Meissner effect is possibly present in this material.

Hongyang Wang1, Yao Yao2†, Ke Shi3, Yijing Zhao3, Hao Wu4, Zhixing Wu5, Zhihui Geng6, Shufeng Ye1, and Ning Chen7
1 Center of Materials Science and Optoelectronics Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100049, China
2 State Key Laboratory of Luminescent Materials and Devices and Department of Physics, South China University of Technology, Guangzhou 510640, China
3 Beijing 2060 Technology Co., Ltd, Beijing 100084, China
4 School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
5 Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food safety, College of Chemistry, Fuzhou University, Fuzhou 350108, China
6 School of Engineering, Course of Applied Science, Tokai University, Hiratsuka 2591292, Japan
7 School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
(Dated: January 3, 2024)

2. Researchers from Six Chinese Universities and research labs have found experimental proof of some superconductivity near room temperature for LK99 material.

School of Minerals Processing and Bioengineering, Central South University, Changsha, China
State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, China
Department of Physics, South China University of Technology, Guangzhou, China
Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou, China
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China

They observe a considerable hysteresis effect of low-field microwave absorption (LFMA) in copper-substituted lead apatite. By continuously rotating samples under external magnetic field, this effect is diminished which can not be renewed by a strong magnetic field but will be spontaneously recovered after two days, indicating its glassy features and excluding possibility of any ferromagnetism. The intensity of LFMA is found to sharply decrease at around 250K, suggesting a phase transition takes place. A lattice gauge model is then employed to assign these effects to the transition between superconducting Meissner phase and vortex glass, and the slow dynamics wherein is calculated as well.

3. Edge-sharing quasi-one-dimensional cuprate fragments in optimally substituted
Cu/Pb apatite

Katherine Inzani, School of Chemistry, University of Nottingham, United Kingdom
John Vinson, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, 20899, USA
Sinead M. Griffin 3Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California

The flurry of theoretical and experimental studies following the report of room-temperature superconductivity at ambient pressure in Cu-substituted lead apatite CuxPb10−x(PO4)6O (‘LK99’) have explored whether and how this system might host strongly correlated physics including superconductivity. While first-principles calculations at low doping (x ≈ 1) have indicated a Cu-d9 configuration coordinated with oxygen giving rise to isolated, correlated bands, its other structural, electronic, and magnetic properties diverge significantly from those of other known cuprate systems. Here we find that higher densities of ordered Cu substitutions can result in the formation of contiguous edge-sharing Cu-O chains, akin to those found in some members of the cuprate superconductor family. Interestingly, while such quasi-one-dimensional edge-sharing chains are typically ferromagnetically coupled along the chain, we find an antiferromagnetic ground-state magnetic order for our cuprate fragments which is in proximity to a ferromagnetic quantum critical point. This is a result of the elongated Cu-Cu distance in Cu-substituted apatite that leads to larger Cu-O-Cu angles supporting antiferromagnetism, which we demonstrate to be controllable by strain. Finally, our electronic structure calculations confirm the low-dimensional nature of the system and show that the bandwidth is driven by the Cu-O plaquette connectivity, resulting in an intermediate correlated regime.

4. The US Air Force Research Lab is funding Chapman University to study and try to replicate thin film LK99. DARPA may be following up with more extensive funding for thin film LK99.

8 thoughts on “Berkeley Supercomputer Modeling and Chinese Experimental Research Says LK99 Variant Superconductors are BACK!”

  1. https://scitechdaily.com/scientists-discover-groundbreaking-superconductor-with-on-off-switches/
    A number of environmental variables can affect the energy bands: an applied voltage, mechanical stress (changes Bloch waves; due to the wave nature of electrons, standing waves of electron wave functions around iron atoms as an example can behave like Japanese Zen rock-art islands’ surrounding waves and interfere with those of neighboring islands resulting in ferromagnetic and diamagnetic patterns,) laser light, introduction of dopant atoms, presence of nearby atoms with resonant masses, etc.

  2. The k in kT is Boltzmann’s Constant=1.3807×10^-23 J/K
    kT is roughly the thermal kinetic energy available to a molecule at absolute temperature T, which is 273.15K at 0C. The reason that a superconductivity-providing band needs to be within kT or so of the Fermi energy is because of the Fermi-Dirac Distribution obeyed by the electrons. There’s an exponentially decaying numerator of the form E/kT so for a large energy E away from Fermi energy, the probability of finding an electrons becomes very small. Electrons *all cooped up* in a rather flat energy bands are needed to make the superconductivity-generating bosons.

  3. Iris Alexandra claimed that sulfur was a common contaminant in the material she used. That’s how sulfur got in: as a dopant “lifting the degeneracy” moving the nearly flat bands of LK-99 near the Fermi energy. As long as one or more is within kT of the Fermi energy, superconductivity may manifest. Flatness counts. Occupancy of the band being high also counts towards superconductivity. The band must be within kT with T~273K to work.

  4. Iris Alexandra, a soil scientist of Moscow, had posted online a video before of a tiny speck extracted from the bulk LK-99 sample she had created. It levitated, probably at room temperature and ambient pressure above a magnet. It looked very much like the Meissner effect to me. I think that this room-temperature ambient-pressure superconductivity claim is REAL.
    The 250K temperature may be a phase change temperature of copper sulfide.

    Iris wrote that she smashed the bulk sample (perhaps with a hammer?) and tested the fragments a tiny piece at a time and found the levitating one.

  5. This is just getting into medieval alchemy now. “We didn’t add any sulphur/ lead/ phlogiston!”. No understanding of why it would make a difference.

    • Iris said that sulfur might have gotten in as an impurity which she didn’t drive off. She was using a much faster process than the original LK-99 researcher. The dopant may have been all important.

  6. If it does pan out (a big if still) it may necessitate a new terminology. “Computer grade room temperature superconductors” for ones you can use for chips and things as opposed to “general room temperature superconductors” which are yet to be discovered but would allow all the fun applications involving magnets and wires and such.

    • I used the term “transductor” when I was discussing computer-related superconductors. The term is analogous to “transistor” but rather than having resistors generating heat, transductor switches superconducting or normal conducting currents generating little heat.

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