excitons tagged posts

Quantum ‘alchemy’ made feasible with excitons

What if you could create new materials just by shining a light at them? To most, this sounds like science fiction or alchemy, but to physicists investigating the burgeoning field of Floquet engineering, this is the goal. With a periodic drive, like light, scientists can “dress up” the electronic structure of any material, altering its fundamental properties—such as turning a simple semiconductor into a superconductor.

While the theory of Floquet physics has been investigated since a bold proposal by Oka and Aoki in 2009, only a handful of experiments within the past decade have managed to demonstrate Floquet effects...

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Sudden breakups of monogamous quantum couples surprise researchers

two layers of a chemical structure lie above each other with black balls hovering on top. On the top layer, there is a cyan ball with a white ball in the corresponding layer below
An exciton forms when an electron pairs up with a hole—a mobile particle-like void in a material where an electron is missing from an atom. When paired up as an exciton, a hole and electron normally travel around together as an exclusive couple, but a new experiment probes what happens when conditions in a material break up the pair. In the image, a hole (grey sphere) resides in the bottom layer of a stacked material and is paired to an electron in the top layer (cyan sphere). None of the electrons present in the top layer (black spheres) are willing to share a spot in the material with each other or the electron in the exciton. (Credit: Mahmoud Jalali Mehrabad/JQI)

Quantum particles have a social life, of a sort...

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Magnetic semiconductor preserves 2D quantum properties in 3D material

The atomic lattice structure of the layered magnetic semiconductor chromium sulfide bromide (CrSBr) have magnetic moments, or spins, that align with each other and alternate on each layer. This ordering enables the confinement of excitons — which are bound electron and hole pairs — to a single layer of CrSBr even inside the 3D material, according to the researchers.  Credit: Provided by Yinming Shao. All Rights Reserved.

Physicists have developed a novel approach to maintain special quantum characteristics, even in 3D materials, with potential applications in optical systems and advanced computing.

There is a big problem with quantum technology — it’s tiny...

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Scientists Trap Light inside a Magnet

Vinod_Florian magneto-optical research
Light trapped inside a magnetic crystal can strongly enhance its magneto-optical interactions. Image created by Rezlind Bushati.

A new study led by Vinod M. Menon and his group at the City College of New York shows that trapping light inside magnetic materials may dramatically enhance their intrinsic properties. Strong optical responses of magnets are important for the development of magnetic lasers and magneto-optical memory devices, as well as for emerging quantum transduction applications.

In their new article in Nature, Menon and his team report the properties of a layered magnet that hosts strongly bound excitons — quasiparticles with particularly strong optical interactions. Because of that, the material is capable of trapping light — all by itself...

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