A puzzle how crystals are semi -forming

The original version to This story Appear Quanta magazine.

Since their discovery in 1982, strange materials known as semi -crystals have physics and chemists. Their atoms themselves are arranged to chains of five -year -old, other forms, and other forms to form patterns that are never repeated. These patterns seem to challenge physical laws and intuition. How can the atoms “know” how to make uneven arrangements without an advanced mathematics understanding?

He said: “The crystals are almost one of those things that as a material world, when you get to know them for the first time, you love,” this is crazy. ” Winno SunMaterial scientist at the University of Michigan.

Recently, though, a set of results exfoliate some of its secrets. in One studySun and collaborators adaptive a way to study crystals to determine that at least some crystals are stable thermal dynamic-their atoms will not be settled in a low energy arrangement. This discovery helps explain how and why crystals are formed. A The second study It has resulted in a new way for the semi -crystal engineer and monitoring them in the training process. And her third research group Record Properties unknown by these unusual materials.

Historically, the crystals were almost difficult to create and describe.

“There is no doubt that they have interesting characteristics,” he said, “He said,” Sharon GluzerAlso -based mathematical physicist at the University of Michigan, but he did not participate in this work. “But the ability to make it in large quantities, to expand its scope, on the industrial level – (that) they did not feel unable, but I think this will start showing how to do this frequently.”

Vikram Javini, Sambit Das, Wahion Pike, Winho Sun and Chipo Tan, have examples of geometric shapes that appear in the semi -crystals. The University of Michigan University researchers have shown that at least some crystals are stable and thermal dynamic.

Photo: Marcin Szczepanski Michigan Engineering

“Prohibited” symmetries

Almost a decade before the Israeli physicist Dan Shukman Discover the first examples of the semi -crystals in the laboratory, the British sports physicist Roger Pinerose thought in “almost almost” – at the most not repeated – that would appear in these materials.

Pinrose Advanced groups of tiles This can cover an endless plane without gaps or overlap, in patterns that are not repeated and unable, and cannot be repeated. Unlike the amplifier made of triangles, rectangles, and my six – scattered across two, three, four or six axes, and any tile area in periodic patterns – five times “banned” covers. Tiles make up five arrangements, however the Pentagon cannot comfortably fit alongside the plane. Therefore, while the tiles aligned along the length of five axes and an endless mosaic, different sections of the style seem similar only; Exclusive repetition is impossible. Penrose semi -cocberry layer lid American scientific In 1977, five years before jumping from pure mathematics to the real world.