A collaborative team of researchers from Rice University, the University of Houston, and the California Institute of Technology have created a pioneering chiral cavity configuration. This dynamic new method has the potential to change the way quantum materials, including graphene, are integrated into tomorrow’s technologies. Main photo credit: Junichiro Kono, the Karl F. Hasselmann Professor of Engineering at Rice, led the multidisciplinary, collaborative study published in Nature Communications. He’s the founding director of Rice’s Smalley-Curl Institute. This innovative basic research has the potential to minimize or even do away with the strong magnetic fields that had hitherto been needed to control materials.
Kono’s expertise in electrical and computer engineering and materials science and nanoengineering underpins the study’s ambitious goals. The interdisciplinary research team, headed by assistant research professor Andrey Baydin, collaborated extensively with graduate students Fuyang Tay and Ceren Dag. They collaborated with Alessandro Alabastri and Stephen Sanders to develop numerical simulations that help put their findings in context.
The Chiral Cavity and Its Implications
The original creative idea was to use an alternative, lightly doped indium antimonide, as a chiral cavity. This realization allows researchers to explore the delicate interplay between chiral vacuum fluctuations and matter — charged, massive particles like neutrinos. Their results might point the way to discovering other properties that would be advantageous to applications for quantum devices.
Developing techniques for control over vacuum fluctuations would open an exciting new frontier for scientific study. The development team is optimistic that their novel cavity design will go on to transform materials. They want to realize these kinds of transformations without going to the limits usually found in quantum material engineering.
“Our chiral cavity offers a platform for harnessing the subtle but powerful quantum effects of vacuum to engineer new material properties, potentially paving the way for novel quantum devices and technologies.”
Baydin went into more detail about why the materials they selected matter, saying,
That’s the implication of a new study, which shows that by depositing graphene over this new cavity, researchers generate a band gap. This change reverses its topological nature and practically turns it into a new kind of insulator. This breakthrough is a big step toward creating new forms of these quantum devices.
“The choice to use lightly doped indium antimonide to construct the cavity made all the difference—it allowed us to turn an ordinary optical cavity into a chiral cavity using a low magnetic field.”
Transformations in Graphene
The research team found that their framework can extend far beyond graphene. This could potentially extend to other materials enmeshed in analogous chiral chambers. Co-author Vasil Rokaj noted,
A key feature of this research is its purpose to reduce and even better profoundly alleviate dependence on high magnetic fields. Historically, material manipulation needed to apply extreme magnetic environments that make experimentation and implementation difficult.
“Based on our calculations, we predicted that placing graphene in this cavity opens a band gap that changes its topological properties and turns it into a special kind of insulator that will be useful for building new types of quantum devices.”
The researchers argue that their model is compatible with strong suppression of vacuum fluctuations in one direction. They are confident this is possible with a relatively small magnetic field, far weaker than what has been required historically, without altering other properties. This would have an enormous potential to reduce the engineering complexity of quantum devices.
“In addition to identifying a novel quantum state for graphene, the framework we built can be extended to other materials embedded in a chiral cavity.”
Reducing Magnetic Field Requirements
Alessandro Alabastri explained how simulations played a pivotal role in their development:
That his hybrid approach increases the team’s predictions accuracy by leaps and bounds. It makes their workflow more efficient, opening up time to test and refine many more possible designs.
“Our goal has been to reduce the required magnetic field or ideally eliminate it entirely.”
The researchers propose that using their model, a small magnetic field—much lower than what has been previously utilized—will suffice to suppress vacuum fluctuations in one direction while leaving other properties intact. This could dramatically simplify the engineering process for quantum devices.
Alessandro Alabastri explained how simulations played a pivotal role in their development:
“Simulations allowed us to refine the cavity design without the need to fabricate physical prototypes, which not only significantly accelerated the development process but also helped us explore a wider range of design parameters efficiently.”
This hybrid approach not only enhances the predictions made by the team but also streamlines their workflow, allowing for more comprehensive exploration of potential designs.