New understanding of charge transport reveals an exotic quantum mechanical regime

phys.org | 9/17/2019 | Staff
ajoy26ajoy26 (Posted by) Level 3
Click For Photo: https://scx2.b-cdn.net/gfx/news/hires/2016/57dfe35e10c2e.jpg

In work that may have broad implications for the development of new materials for electronics, Caltech scientists for the first time have developed a way to predict how electrons interacting strongly with atomic motions will flow through a complex material. To do so, they relied only on principles from quantum mechanics and developed an accurate new computational method.

Studying a material called strontium titanate, postdoctoral researcher Jin-Jian Zhou and Marco Bernardi, assistant professor of applied physics and materials science, showed that charge transport near room temperature cannot be explained by standard models. In fact, it violates the Planckian limit, a quantum speed limit for how fast electrons can dissipate energy while they flow through a material at a given temperature.

Work - Physical - Review - Research - December

Their work was published in the journal Physical Review Research on December 2.

The standard picture of charge transport is simple: electrons flowing through a solid material do not move unimpeded but instead can be knocked off course by the thermal vibrations of atoms that make up the material's crystalline lattice. As the temperature of a material changes, so too does the amount of vibration and the resulting effect of this vibration on charge transport.

Vibrations - Quasiparticles - Phonons - Excitations - Materials

Individual vibrations can be thought of as quasiparticles called phonons, which are excitations in materials that behave like individual particles, moving and bouncing around like an object. Phonons behave like the waves in the ocean, while electrons are like a boat sailing across that ocean, jostled by the waves. In some materials, the strong interaction between electrons and phonons in turn creates a new quasiparticle known as a polaron.

"The so-called polaron regime, in which electrons interact strongly with atomic motions, has been out of reach for first-principles calculations of charge transport because it requires going beyond simple perturbative approaches to treat the strong electron-phonon interaction," says Bernardi. "Using a...
(Excerpt) Read more at: phys.org
Wake Up To Breaking News!
Sign In or Register to comment.

Welcome to Long Room!

Where The World Finds Its News!