Adiabatic dechiralisation and thermodynamics of Weyl semimetals

We study thermodynamic manifestations of the chiral anomaly in disordered Weyl semimetals. We focus, in particular, on the effect which we call "adiabatic dechiralisation", the phenomenon in which a change in temperature and/or an absorption or release of heat results from changing external electric and magnetic fields that change the imbalance of quasiparticles with different chiralities (at different Weyl nodes). This effect is similar to that of adiabatic demagnetisation, which is commonly used as a method of low-temperature refrigeration. We describe this phenomenon quantitatively and discuss experimental conditions favourable for its observation. A related phenomenon, which we analyse and which is readily observable in experiment, is the dependency of the heat capacity of a Weyl semimetal on parallel electric and magnetic fields.