They just have tiling that is locally regular but has no long-range order, like Penrose tiles.
(left: a real microscopy image. right: Penrose tiles)
Conversation
All the quasicrystals we have found on earth are apparently meteorite fragments.
If you ever want to hear an incredible, adventurous science talk, listen to Paul Steinhardt talk about leading an expedition into Kamchatka to find them:
1
2
27
39. Most materials expand in one direction when you compress them in a perpendicular direction. But AUXETICS are materials that either shrink or expand in both directions simultaneously.
(In engineering terms, they have a negative "Poisson ratio")
GIF
1
2
20
There are lots of fun engineering examples of auxetics. But they also appear naturally. Here's one, for example ("cristobalite", a variant of quartz):
1
12
40. OPTICAL METAMATERIALS are human-made materials in which a bunch of small electromagnetic resonators are arranged so that their interactions produce unusual behaviors of light (or EM waves in some band of frequency). For example, you can engineer negative index of refraction!
2
2
17
41. There is a lot of excitement and mystery right now about SAMARIUM HEXABORIDE, which looks simultaneously like an insulator and a quantum metal, in ways that we are still grappling with.
See this earlier thread: (twitter.com/gravity_levity)
Quote Tweet
30/30 Since this is a paper whose major point is mostly to rain on a fun quantum hype parade, I expect it to be essentially ignored.
Show this thread
3
10
I think that I am out of time and energy now, and tired of spamming your timelines. So let's draw this thread to an
END.
Thank you all for coming along with me. It's been fun, and nothing at all like a systematic list of "the 100 most interesting materials".
8
1
38
I didn't get to 100, but this thread has at least 100 tweets in it and I am now reporting for debriefing
4
12
Replying to
Now I want to start my own museum of materials and buy a microscope to look at them with 🤔
Replying to
If you ever get a chance to go to the Harvard museum, check out their minerology room. It's the best "shock and awe" display of materials that I've eve seen.
1
1
Replying to
Kinda hard to make a museum of though, since so many materials don’t have visually obvious interesting properties... I think I went to one where there were little balls of metals that all looked the same but you could lift them to feel the weight difference
1

