Physicists first capture a strange fractal “butterfly”

A fractal pattern, made of a rare alignment of magnetic fields, was planned for the first time 50 years ago, but only now could it be captured.

Computer scientist Douglas Hofstadter predicted in the 70s that, when certain two -dimensional crystals were placed in magnetic fieldsthe energy levels of their electrons produced a strange standard that looked the same, regardless of the distance to which zoomknown as Fractal, tells.

In 2013, it was possible nitreto de boro, a material similar to graphene.

The repetitive patterns that make up this amazing “butterfly” come when two layers of graphene, one overlaid to another, reach one “magical angle ”.

This alignment can even give rise to rare properties, such as superconductivity, mass the strong magnetic fields distort the electrons from the graphene, making them impossible to measure in detail with an electronic microscope. Until now.

In a new published in NatureThere Yazdani of the University of Princeton, and his colleagues measured the now called Hofstadter butterfly In detail for the first time, using two layers of graphene.

“The fact that we can go to these very low magnetic fields and make this experience was a bass point that people had not predicted before,” explains Yazdani.

“It’s a good story that shows the forecast power we have,” says Johannes Lischner, researcher at Imperial College of London. “We really understand the fundamental laws of electrons, In such a way that we can make a forecast and even if 50 years are needed to check it, in the end it is expected. ”

And even the “father” of these fractals, Douglas Hofstadter, is “very pleased” with the new developments: “I have left physics for about 50 years and, therefore, I can not make any professional judgment about it. Needless to say that I am always satisfied when there are empirical confirmations of the structure I predicted in 1976. ”