Imperfections reveal unexpected links between light and atomic vibrations in ultrathin boron nitride
First, one person stands up, followed by their neighbors, one after another, until a wave sweeps through the stadium. Atoms within a material move in a similar way: rather than remaining completely still in their positions, they vibrate together around their respective positions. In physics, these collective lattice vibrations are known as "phonons." Some of them can interact with light and…
Scientists from Kiel University have discovered how imperfections in an ultrathin material, hexagonal boron nitride, can interact with atomic vibrations to produce coherent light emission. When light interacts with the atomic lattice, the oscillations of atoms are known as phonons. These phonons can sometimes interact with light, changing its energy in the process.
In their study, published in Advanced Functional Materials, Professor Nahid Talebi and her team found that tiny irregularities, or point defects, in the atomic structure of hexagonal boron nitride can act as quantum emitters, emitting individual light particles and interacting strongly with phonons. This interaction can disrupt the defects' quantum properties, resulting in synchronized emission of light waves, known as coherent light emission.
The researchers illuminated hexagonal boron nitride with laser light and observed that, in addition to the expected light emission from the defects, they detected another light signal with lower energy than the incoming laser light. This energy difference corresponds to specific phonons in the atomic lattice, which normally would not participate in this form of light scattering due to crystal symmetry.
However, the interaction between quantum emitters and phonons enabled this coherent light emission when the material was illuminated with laser light, but not with an electron beam. The study suggests that controlling the number of point defects in hexagonal boron nitride could enable the development of new light sources with quantum properties.
Written by urgent.news from Phys.org's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
