Bayerisches Geoinstitut, Universität Bayreuth, 95440 Bayreuth, Germany and Yale University, New Haven, Connecticut 06511, USA.
Swedish e-Science Research Centre (SeRC), Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden and Centre de Physique Théorique, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France.
Phys Rev Lett. 2013 Mar 15;110(11):117206. doi: 10.1103/PhysRevLett.110.117206. Epub 2013 Mar 12.
We discover that hcp phases of Fe and Fe(0.9)Ni(0.1) undergo an electronic topological transition at pressures of about 40 GPa. This topological change of the Fermi surface manifests itself through anomalous behavior of the Debye sound velocity, c/a lattice parameter ratio, and Mössbauer center shift observed in our experiments. First-principles simulations within the dynamic mean field approach demonstrate that the transition is induced by many-electron effects. It is absent in one-electron calculations and represents a clear signature of correlation effects in hcp Fe.
我们发现，Fe 和 Fe(0.9)Ni(0.1)的 hcp 相在约 40 GPa 的压力下经历了一个电子拓扑转变。费米面的这种拓扑变化通过我们实验中观察到的德拜声速、c/a 晶格参数比和穆斯堡尔中心位移的异常行为表现出来。动态平均场方法中的第一性原理模拟表明，这种转变是由多电子效应引起的。在单电子计算中不存在这种转变，这是 hcp Fe 中关联效应的明显特征。
