LK-99, a room temperature superconductor?

[SpankyMcFarland]

Given that nobody else has had a go at this potentially important topic, I will do my blissfully ignorant, copy-and-pasting best and hope that somebody better informed steps in to rescue the thread.

Like cold fusion, room temperature superconductivity is one of those advances that has long been predicted but has yet to arrive. Superconductivity at any temperature or pressure sounds like a magical state where electrical resistance and magnetic flux fields abruptly vanish as the temperature of a material is lowered below a critical point. Get this: an electrical current through a superconducting wire could continue indefinitely. The possible technological consequences of being able to do this at room temperature are obvious.

Cast your minds back to high school and Ohm’s Law which states that the current through a conductor between two points is directly proportional to the voltage across those two points. Introducing the constant of proportionality, resistance, one arrives at mathematical equations to describe this relationship:

where I is the current through the conductor, V is the voltage measured across the conductor and R is the resistance of the conductor.

After Ohm’s law was accepted, it was discovered that the resistance of conductors reduced gradually as temperature declined. However, in 1911 Heike Onnes amazed the world by demonstrating that when Mercury was cooled a lot, to 4K (-269C), it abruptly lost all resistance, an extraordinary and, at the time, inexplicable finding. It was left to quantum physics to supply an answer - the BCS theory which explained the superconducting current as a superfluid of Cooper pairs, i.e. pairs of electrons interacting through the exchange of phonons. 

Another major advance occurred in 1986 when it was discovered that some cuprate ceramic materials have a critical temperature above 90 K (−183 °C). They were called high temperature superconductors, which seems strange until one recalls that liquid nitrogen boils at 77 K (−196 °C). Consequently, superconductivity at higher temperatures than this opens up applications that are much trickier at lower temperatures.

Fast forward to 2023. A South Korean group has just claimed to have discovered a room temperature superconductor, LK-99.

Quote

A Korean team’s claim to have discovered a superconductor that works at room temperature and ambient pressure has become a viral sensation — and prompted a slew of replication efforts by scientists and amateurs alike. But initial efforts to experimentally and theoretically reproduce the buzzworthy result have come up short, and researchers remain deeply sceptical.

The research team, led by Sukbae Lee and Ji-Hoon Kim at the start-up firm Quantum Energy Research Centre in Seoul said in preprints published on 25 July^1,2 that a compound of copper, lead, phosphorus and oxygen, dubbed LK-99, is a superconductor at ambient pressure and temperatures above 127 °C (400 Kelvin). The team claims that samples show two key signs of superconductivity: zero electrical resistance and the Meissner effect, in which the material expels magnetic fields, leading samples to levitate above a magnet. Previous efforts have achieved superconductivity only in certain materials under incredibly low temperatures or extremely high pressures. No material has ever been confirmed to be a superconductor under ambient conditions.

Unfortunately, the sceptics are getting louder every day:

Quote

The first attempts to replicate LK-99, reported in the past days, have not improved the material’s prospects. None of the studies provide direct evidence for any superconductivity in the material. (The Korean team did not respond to Nature’s request for comment.)

Two separate experimental efforts by teams at the National Physical Laboratory of India in New Delhi³ and Beihang University in Beijing⁴, reported synthesizing LK-99, but did not observe signs of superconductivity. A third experiment by researchers at Southeast University in Nanjing⁵ found no Meissner effect, but measured near zero resistance in LK-99 at -163 °C (110 K) — which is far below room temperature, but high for superconductors.

https://www.nature.com/articles/d41586-023-02481-0
 

While ‘we’ may be back to the drawing board/test tube/computer model very shortly, it’s certainly a quest that will continue. 

 

Edited August 5, 2023 by SpankyMcFarland

[Legato]

Would be an amazing discovery if ever solved.

We need to take a trip to Pandora for some unobtanium.

[SpankyMcFarland]

I think hope is fading fast for LK-99 but we’ll see stronger candidates in the future. 

[SpankyMcFarland]

Oh dear me, LK-99 seems to be the opposite of a superconductor:

Quote

Superconductivity begins at a critical temperature below which the material can transmit electricity with no resistance. According to some of the new data, the resistivity of LK-99 increases as you lower the temperature, like some sort of anti-superconductor.

https://www.iflscience.com/hopes-dashed-as-lk-99-confirmed-not-to-be-a-room-temperature-superconductor-70165

 

And that levitation video? 

https://www.tomshardware.com/news/lk-99-video-fraud-taken-down

 

There’s a similar video from Wuhan university that is still up. As if that city needed any more bad publicity. 

 

 

Edited August 8, 2023 by SpankyMcFarland

[Aristides]

Shades of cold fusion. 

[SpankyMcFarland]

A failure for these scientists but a success for science. A claim was rapidly tested and found to be false. 

[Dictatords]

I appreciate you bringing up such an intriguing topic for discussion. Room temperature superconductivity has been a holy grail in the realm of physics for decades, offering immense promise for revolutionizing various industries. Imagine the possibilities if we could achieve superconductivity at everyday temperatures, where electrical currents flow endlessly without any resistance. It could pave the way for groundbreaking advancements in technology, from more efficient power transmission to ultra-fast computing.