Anomalous melting behavior under extreme conditions: hard matter turning "soft"

TL;DR

This paper demonstrates that particles interacting via the exp-6 potential exhibit anomalous melting behaviors like reentrant melting and complex solid phases under high pressure, revealing similarities between atomic and soft matter.

Contribution

It uncovers the connection between high-pressure melting anomalies and local order crossover in systems with exp-6 interactions, providing a unified understanding.

Findings

Observation of reentrant melting and polymorphism in exp-6 systems

Identification of a stable BC8 crystal phase at high pressure

Linking melting anomalies to local order crossover

Abstract

We show that a system of particles interacting through the exp-6 pair potential, commonly used to describe effective interatomic forces under high compression, exhibits anomalous melting features such as reentrant melting and a rich solid polymorphism, including a stable BC8 crystal. We relate this behavior to the crossover, with increasing pressure, between two different regimes of local order that are associated with the two repulsive length scales of the potential. Our results provide a unifying picture for the high-pressure melting anomalies observed in many elements and point out that, under extreme conditions, atomic systems may reveal surprising similarities with soft matter.