excitons tagged posts

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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Tunable Quantum Traps for Excitons

Visualisation of the electrical trap
A laser beam (orange) creates excitons (purple) that are trapped inside the semicondcutor material by electric fields. (Image: Puneet Murthy / ETH Zurich)

Researchers at ETH Zurich have succeeded for the first time in trapping excitons—quasiparticles consisting of negatively charged electrons and positively charged holes—in a semiconductor material using controllable electric fields. The new technique is important for creating single photon sources as well as for basic research.

In semiconductor materials, electric current can be conducted both by electrons and by positively charged holes, or missing electrons. Light hitting the material can also excite electrons to a higher energy band, leaving behind a hole in the original band...

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Lasers Trigger Magnetism in Atomically Thin Quantum Materials

A cartoon depiction of the light-induced ferromagnetism that the researchers observed in ultrathin sheets of tungsten diselenide and tungsten disulfide. Laser light, shown in yellow, excites an exciton – a bound pair of an electron (blue) and its associated positive charge, also known as a hole (red). This activity induces long range exchange interactions among other holes trapped within the moiré superlattice, orienting their spins in the same direction.Xi Wang/University of Washington

Researchers have discovered that light – in the form of a laser – can trigger a form of magnetism in a normally nonmagnetic material. This magnetism centers on the behavior of electrons...

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Evidence for Exotic Magnetic Phase of Matter

Scientists identify a long-sought magnetic state predicted nearly 60 years ago. Scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have discovered a long-predicted magnetic state of matter called an “antiferromagnetic excitonic insulator.”

“Broadly speaking, this is a novel type of magnet,” said Brookhaven Lab physicist Mark Dean, senior author on a paper describing the research just published in Nature Communications. “Since magnetic materials lie at the heart of much of the technology around us, new types of magnets are both fundamentally fascinating and promising for future applications.”

The new magnetic state involves strong magnetic attraction between electrons in a layered material that make the electrons want to arrange their magnetic moments, o...

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