---

※ 引述《kairiyu (E N O U G H  is  enough)》之銘言：
: 超導體能源聖杯破滅 LK-99非超導體

: 。科學偵探們發現，樣品電阻率急速下降，且得以部分懸浮在磁鐵上，是因為材料中有雜
質，尤其是硫化亞銅。這項結論讓LK-99作為史上首個常溫常壓超導體的希望徹底破滅。


https://www.nature.com/articles/d41586-023-02585-7
Nature 上刊登的這篇新聞，重點在於雜質硫化亞銅(Cu2S) 打破了 LK-99超導體的希望，
我截取了其中提到用實驗證明了雜質影響的論文


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On 8 August, the CAS team reported on the effects of Cu2S impurities in LK-99.
“Different contents of Cu2S can be synthesized using different processes,” say
s Jianlin Luo, a CAS physicist. The researchers tested two samples — the first
heated in a vacuum, which resulted in 5% Cu2S content, and the second in air, wh
ich gave 70% Cu2S content.



The first sample’s resistivity increased relatively smoothly as it cooled, and
appeared similar to samples from other replication attempts. But the second samp
le’s resistivity plunged near 112 ºC (385K) — closely matching the Korean team
’s observations.

第一個樣品的電阻率隨著溫度冷卻而相對平穩的上升，與其它復現的樣品相似。 但第二個
樣品的電阻率在 112 ºC (385K)附近時急遽下降，相當符合韓國團隊觀測的結果。

“That was the moment where I said, ‘Well, obviously, that’s what made them th
ink this was a superconductor,’” says Fuhrer. “The nail in the coffin was thi
s copper sulfide thing.”

Fuhrer 表示“那時我就說‘顯然這就是讓他們認為是超導體的原因’”。 “copper sulfi
de 就是最好的證據。”

*copper sulfide 指的是硫化銅一族

------------------------------------------------
On 14 August, a separate team, at the Max Planck Institute for Solid State Resea
rch in Stuttgart, Germany, reported synthesizing pure, single crystals of LK-99.
 Unlike previous synthesis attempts that relied on crucibles, the researchers us
ed a technique called floating zone crystal growth that allowed them to avoid in
troducing sulfur into the reaction, eliminating the Cu2S impurities.



The result was a transparent purple crystal — pure LK-99, or Pb8.8Cu1.2P6O25. S
eparated from impurities, LK-99 is not a superconductor, but an insulator with a
 resistance in the millions of ohms — too high to run a standard conductivity t
est. It shows minor ferromagnetism and diamagnetism, but not enough for even par
tial levitation. “We therefore rule out the presence of superconductivity,” th
e team concluded.




* 編輯下補上 Nature 的原文網址

※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 1.162.126.102 (臺灣)
※ 作者: kkm99 2023-08-19 09:35:30
※ 文章代碼(AID): #1au1naz9 (Stock)
※ 文章網址: https://www.ptt.cc/bbs/Stock/M.1692408932.A.F49.html