Original title: Electron-phonon coupled hydrodynamics in semimetal TaAs_2
Shan Jiang, Wei Xie, Xiaokang Li, Kamran Behnia +1 · September 2026
Inside solids, heat and electricity usually move by diffusion, with particles bouncing around randomly. But when particles collide mostly by swapping momentum without losing it, they can flow together like a fluid. Scientists tested crystals of TaAs2 with different impurity levels using electrical and thermal measurements. They found that between 5 and 15 K, electrons and lattice vibrations, called phonons, join into a single coupled fluid. Phonons flow like liquid in a pipe, making heat conduct faster than T^3. At the same time, strong ties between electrons and phonons stop phonons from moving freely without collisions. Heat conduction also shows quantum oscillations. Finally, this joint fluid causes a large violation of the Wiedemann-Franz law and a two-order-of-magnitude gap in electron lifetimes.
Imagine walking through a crowded hallway where people are moving in both directions. Normally, you can dodge others and find your own path, but if the hallway is too crowded, you all bump into each other and move together in a coordinated flow. In this paper, electrons and phonons are like the people in the hallway. At low temperatures in TaAs2, they collide frequently, causing them to flow together as a single fluid, altering heat and electricity transport.
This shows how particles interact in materials at extreme cold, affecting heat and charge transport. It could guide the development of materials for low-temperature technologies.
The abstract does not state whether this phenomenon occurs in other materials or at higher temperatures. It focuses only on TaAs2 within the 5-15 K range.
Ask anything about this paper. Answers come from its abstract, and say so when the abstract doesn't cover your question.
Electron-phonon coupled hydrodynamics in semimetal TaAs_2 — Shan Jiang, Wei Xie, Xiaokang Li et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.