  It is often assumed that atoms are hard spheres in the estimation of local
lattice distortion (LLD) in high-entropy alloys (HEAs). However, our study
demonstrates that the hard sphere model misses the key effect, charge transfer
among atoms with different electronegativities, in the understanding of the
stabilization of severely-distorted HEAs. Through the characterization and
simulations of the local structure of the HfNbTiZr HEA, we found that the
charge transfer effect competes with LLD to significantly reduce the average
atomic-size mismatch. Our finding may form the basis for the design of severely
distorted, but stable HEAs.
