New research finds evidence of wave conversion in quantum matter. Their findings (Scientists observe heat waves traveling through metal) defy expectations about how metal creates light and can push images beyond the limits of visual perception.
When we encounter jewels in our daily life, we realize that they shine. This is because metals typically glow in the visible wavelength range and reflect back any light that falls on them. Although metals are well suited for conducting electricity and heat, they are not considered good conductors of heat.
But in the field of quantum computing, researchers are finding more and more promising examples of how things should behave. In a new study published in Science Advances, a group led by Dmitri Basov, Professor Higgins of Physics at Columbia University, describes a metal that can guide light through it. “These findings challenge our everyday experience and common sense,” Basov said.
The work is done by Yinming Shao, now a postdoctoral fellow at Columbia who transferred as a doctoral student when Basov moved his laboratory to the University of California, San Diego and New York in 2016. While he and Basov’s team work, Shao examined the telescope. Properties of a semi-metallic material called ZrSiSe. In 2020 in Nature Physics, Shao and colleagues showed that ZrSiSe shares electronic similarities with graphene, a material first discovered by Dirac in 2004. ZrSiSe, however, has enhanced electronic interactions that are rare for Dirac semiconductors.
Although graphene is a single, soft atom of carbon, ZrSiSe is a three-dimensional metal crystal with layers that behave differently in-plane and out-of-plane, known properties exist to anisotropy. “It’s like a sandwich: one layer acts as steel while the next layer acts as insulation,” Shao explained. “When this happens, the fire begins to interact with the metal in a special way at certain times. Instead of just walking around, it can go through the material in a zigzag pattern, which we call hyperbolic circulation.
In their current work, Shao and colleagues at Columbia and the University of California, San Diego found such zigzag light patterns, called hyperbolic waveguide modes, from ZrSiSe samples of variable thickness. Such waves can guide light through matter and where the photons of light mix with the oscillations of electrons to create hybrid quasi-particles called plasmons.
Although the conditions for creating plasmons that can propagate hyperbolically exist in many flat metals, it is the special type of electrical energy level, called the electronic band structure, of ZrSiSe that allowed the team to observe them in ‘to do this. Theoretical support to help interpret these experimental results came from Andrey Rikhter and Michael Fogler’s team at UC San Diego, Umberto De Giovannini and Angel Rubio at the Max Planck Institute for Structure and Dynamics of Matter, and Raquel Queiroz and Andrew Millis at Columbia. . (Rubio and Millis are also affiliated with the Flatiron Institute of the Simons Foundation).
Plasmons can “magnify” features and observations, allowing researchers to see beyond the complexity of optical microscopes, which cannot resolve details much smaller than the wavelengths of light they use. “Using hyperbolic plasmons, we can resolve features smaller than 100 nanometers using infrared light that is hundreds of times longer,” Shao said.
ZrSiSe can be cut to different thicknesses, making it an attractive choice for nano-optics probes that support critical components, Shao said. But it may not only be practical – from there, the team wants to explore others that share similarities with ZrSiSe but may have more attractive properties. This could help researchers to develop more efficient optical chips and better nano-optical methods to investigate fundamental questions about quantum matter.
