Metals have electrons that are expected to be diffusive in movement. They operate as particles, and don't gain momentum together.
Scientists have discovered a type if metal where electrons flow fluidly like water in pipes. This is thanks to interaction with quasiparticles called Phonons. These particles are created from vibrations within a crystal structure.
The electrons' behavior changes from particle-like to fluid-like to diffusive.
According to the research team, this superconductor is made from a combination of niobium (NbGe2) and germanium (Ditelide). It could lead to a new kind of electronic device.
Fazel Tafti, an experimental physicist at Boston College, says that "we wanted to test a recently predicted of the 'electronphonon fluid'."
"Typically electrons are scattered with phonons, which leads to the diffusive motion of electrons within metals. New theory suggests that electrons can interact strongly with phonons to form an electron-phonon liquid. This liquid will flow within the metal in exactly the same manner as water does in a pipe.
(Fazel Tfti, Boston College).
Above: A small crystal of new material, on a device. The inset shows the atomic arrangement.
Tafti's colleagues developed three experimental methods to confirm the electron-photon fluid hypothesis. The first method was to measure the electrical resistivity of the metal. This revealed that its electrons were heavier than is normally expected.
Raman scattering laser analysis revealed that NbGe2's vibration was affected by the unusual flow electrons. Finally, X-ray Diffraction techniques revealed its crystal structure.
A quantum oscillations material mapping approach showed that the mass of electrons was three-times greater than it should have been. This is another indication that electrons and/or phonons were causing unusual behavior.
Tafti says, "This was really surprising because we didn't expect such 'heavy electrons’ in a seemingly straightforward metal."
"Eventually we realized that the strong electron-phonon interactions was responsible for heavy electron behavior. The strong interaction of electrons with lattice vibrations or phonons makes them 'dragged' through the lattice, making it appear that they have gained mass and are heavy.
The idea of electron-phonon fluids is attracting a lot research attention, even though it's not clear what their implications could be for future electronic gadgets and communications systems.
The new research opens up many interesting avenues for future research. The researchers are now looking for other materials that can behave similarly to NbGe2 and will work to control the flow of electrons in future applications.
The researchers explained that electron-phonon scattering reduces electron's momentum within metals. However, a constant exchange of momentum between electrons and phonons could preserve total momentum and result in a coupled electron/phonon liquid.
"Such a phase could be used to observe electron hydrodynamics."
Nature Communications published the research.
