AFRL experiments with heat flow to manipulate quantum materials > ONE AFRL / TWO SERVICES > Article Display
WRIGHT PATTERSON AIR FORCE BASE, Ohio (AFRL) —
The Air Force Research Laboratory, or AFRL, Nano Electronic Materials Branch, part of the Materials and Manufacturing Directorate, has used heat flow experiments to manipulate quantum materials to work in new and different at higher temperatures.
“The question we are exploring in our lab is: what are the limits of phonon engineering without cryogenics to protect delicate quantum systems from the noisy thermal environment?” said AFRL researcher Dr. Chandriker Kavir Dass.
Quantum information science is a field of research involving the generation, manipulation, and measurement of quantum systems such as single atoms, atomic defects in solid-state crystalline materials, or superconducting electronic circuits. AFRL researchers are particularly interested in solid-state quantum science, a field that explores quantum physics in crystalline materials such as 2D materials, silicon carbide and diamond – innovative materials with high potential for future technologies. However, working with quantum systems in these semiconductor platforms is complicated, especially at room temperature.
To remove the influence of phonons on quantum systems at higher temperatures, AFRL researchers are exploring manipulations of material structure and internal stress to reflect, absorb, or “freeze” lattice vibrations that disrupt sensitive quantum systems.
“Just as a sound engineer will acoustically isolate a room to eliminate noise in the recording, or a guitarist will stretch a guitar string to select a particular frequency while freezing low frequencies, we explore these same ideas in quantum systems” , Kavir said.
At room temperature, the atoms that make up these materials vibrate violently, creating what we call heat and sound in the network of materials. In scientific language, these vibrations are called phonons. Phonons can quickly destroy delicate quantum systems within the host material, so researchers typically cool materials to very low temperatures to avoid these problems.
Maintaining a cold environment requires bulky, power-hungry equipment unsuitable for many potential applications within the Department of the Air Force, or DAF. In response to this problem, AFRL researchers are looking for a solution.
Researchers are experimenting with 2D materials like graphene and other 2D materials that can withstand large amounts of stress before breaking. A particular area of interest is that of nano/micro electromechanical systems, or NEMS/MEMS. Found in everything from phones and cars to navigation systems and game controllers, these devices are universal, but researchers want to harness quantum physics and improve these technologies.
In the NEMS/MEMS field, efforts are being made to increase the operating frequencies by reducing the devices or tightening the vibrating elements. By pushing the operating frequencies high enough, the thermal noise is effectively “frozen” and it becomes possible to operate these devices in a quantum regime without the need to cool them to low temperatures. Over the past year, AFRL has invested in understanding and engineering phonon dynamics in quantum systems with the goal of enabling quantum technologies that operate at room temperature.
“If we can control and harness how quantum systems interact with the surrounding environment, we can increase the operating temperature of the system,” said AFRL researcher Dr Robert Bedford. “This will have a big impact on the suitability of quantum sensing, network and timing in DAF-relevant environments and will have a big impact on ground and space applications.”
About the AFRL