2026/01/09 by Yisheng Chai
Physics and Astronomy · #cond-mat.str-el
published as National Science Open, Volume 5(2), 2026, pp.1-4 · Perspective, accepted in National Science Open
arxiv created 2026/01/09 · arxiv updated 2026/07/31
In thermodynamics, volume is an essential extensive variable. Strain-line, area, or volume change-therefore offers a direct window into correlated quantum matter: tiny length changes ΔL track how the lattice responds when state variables such as magnetic field H and/or temperature T are varied, revealing phases, transitions, and dynamics. Direct, high-precision strain measurements are already difficult; their susceptibilities are harder still. Very recently, several direct techniques have made vital progress on two key quantities: the magnetostrictive coefficient dλ/dH (often denoted qijk or dij in the magnetostriction literatures), and the linear thermal-expansion coefficient α= dλ/dT. Considering these two strain susceptibilities together-they are fundamental and complementary-clarifies why these thermodynamic properties merit renewed attention.