Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA.
TCM Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
Phys Rev Lett. 2018 Jul 6;121(1):015301. doi: 10.1103/PhysRevLett.121.015301.
We investigate the binary phase diagram of helium and iron using first-principles calculations. We find that helium, which is a noble gas and inert at ambient conditions, forms stable crystalline compounds with iron at terapascal pressures. A FeHe compound becomes stable above 4 TPa, and a FeHe_{2} compound above 12 TPa. Melting is investigated using molecular dynamics simulations, and a superionic phase with sublattice melting of the helium atoms is predicted. We discuss the implications of our predicted helium-iron phase diagram for interiors of giant (exo)planets and white dwarf stars.
我们使用第一性原理计算研究了氦和铁的二元相图。我们发现，在 terapascal 压力下，氦在环境条件下是一种惰性的稀有气体，与铁形成稳定的结晶化合物。在高于 4 TPa 的压力下形成 FeHe 化合物，在高于 12 TPa 的压力下形成 FeHe2 化合物。我们使用分子动力学模拟研究了熔化过程，并预测了氦原子亚晶格熔化的超离子相。我们讨论了我们预测的氦-铁相图对巨行星（系外行星）和白矮星内部的影响。
