Lead and tellurium semiconductors, manipulated by Rice University physicist Junichiro Kono and postdoctoral researcher Andrey Baydin, elicited a surprising response (PbTe). A strong magnetic field was used to manipulate the “soft” optical phonon mode of the small sample.
Although sound waves are generated and materials’ thermal conductivity is affected by the oscillations of neighboring atoms in opposite directions when an object is subjected to an electrical field similar to that produced by an optical phonon, as opposed to an acoustic phonon. Therefore, “”optical” tag.
Using magnetic fields as low as 9 Tesla, researchers discovered the material’s phononic magnetic circular dichroism, a phenomenon in which right-handed phonons are excited by left-handed magnetic fields and vice versa. While refrigerator magnets are only 5 milliTesla, or 45,000 times weaker, this is the strongest magnet in the world.
In nuclear magnetic resonance devices, a feature known as Zeeman splitting occurs when spectral lines split apart like light through a prism in a magnetic field. Pumping the field to 25 Tesla induced this phenomenon in the sample. The magnetic field also had an effect on the lines. According to their findings, these effects were far more pronounced than predicted by theory.
Physicists have discovered a new way to control phonons, according to Kono, the study’s author. “Phonons are usually not affected by magnetism, so no one expected that they could be controlled by a magnetic field.”
In Kono’s lab, a tabletop spectrometer known as RAMBO (the Rice Advanced Magnet with Broadband Optics) is used to cool materials and expose them to high magnetic fields. By using lasers, researchers can monitor the movement of electrons and atoms within the sample.
Under the conditions of low temperature, magnetized, and triggered by terahertz waves imposed by RAMBO, atoms react differently. Phonons can be detected by the spectrometer’s detection of polarized light absorption.
Co-author Baydin, a postdoc in Kono’s lab, explained that the magnetic field “The magnetic field forces these ions to oscillate in a circular orbit,” “These phonons have a very large effective magnetic moment as a result.
When it comes to high magnetic fields, there are no phonon-electron resonant interactions, so it is not possible that electrons were responsible for the magnetic response of these particles.” “Unexpectedly, the phonons’ own magnetic field response has been observed, which was previously unheard of and unthinkable.
The potential applications of this discovery, according to Kono, are still unclear, but he expects quantum technologists to take notice. A magnetic field can now be used to control phonons, which has important implications for quantum phononics, according to this unexpected discovery.
The paper’s co-lead authors are Felix Hernandez of Brazil’s University of So Paulo and Martin Rodriguez-Vega of Los Alamos National Laboratory. Fuyang Tay, a graduate student in applied physics at Rice, and alumnus Timothy Noe of Rice are also co-authors of the study.
