Weak doping dependence of the antiferromagnetic coupling between nearest-neighbor Mn2+ spins in (Ba1−xKx)(Zn1−yMny)2As2

作     者：Surmach, M.A. Chen, B.J. Deng, Z. Jin, C.Q. Glasbrenner, J.K. Mazin, I.I. Ivanov, A. Inosov, D.S. 

作者机构：Institut für Festkörper- und Materialphysik TU Dresden DresdenD-01069 Germany Institute of Physics Chinese Academy of Sciences Beijing100190 China Center for High Pressure Science and Technology Advanced Research Beijing100094 China School of Physics University of Chinese Academy of Sciences Beijing100049 China Collaborative Innovation Center of Quantum Matter Beijing China Department of Computational and Data Sciences Center for Simulation and Modeling George Mason University 4400 University Drive FairfaxVA22030 Code 6393 Naval Research Laboratory WashingtonDC20375 United States Institut Laue-Langevin 71 avenue des Martyrs CS 20156 Grenoble Cedex 9F-38042 France 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2018年

核心收录：

主　　题：Ferromagnetism 

摘      要：Dilute magnetic semiconductors (DMS) are nonmagnetic semiconductors doped with magnetic transition metals. The recently discovered DMS material (Ba1−xKx)(Zn1− yMny)2As2 offers a unique and versatile control of the Curie temperature, TC, by decoupling the spin (Mn2+, S = 5/2) and charge (K+) doping in different crystallographic layers. In an attempt to describe from first-principles calculations the role of hole doping in stabilizing ferromagnetic order, it was recently suggested that the antiferromagnetic exchange coupling J between the nearest-neighbor Mn ions would experience a nearly twofold suppression upon doping 20% of holes by potassium substitution. At the same time, further-neighbor interactions become increasingly ferromagnetic upon doping, leading to a rapid increase of TC. Using inelastic neutron scattering, we have observed a localized magnetic excitation at about 13 meV, associated with the destruction of the nearest-neighbor Mn – Mn singlet ground state. Hole doping results in a notable broadening of this peak, evidencing significant particle-hole damping, but with only a minor change in the peak position. We argue that this unexpected result can be explained by a combined effect of superexchange and double-exchange interactions. Copyright © 2018, The Authors. All rights reserved.