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

Article

关键词: DILUTE MAGNETIC SEMICONDUCTORS;    NEUTRON-SCATTERING;    ISOLATED CLUSTERS;    FERROMAGNETISM;    DYNAMICS;   

DOI  :  10.1103/PhysRevB.97.104418

来源: SCIE

【 摘 要 】

Dilute magnetic semiconductors (DMS) are nonmagnetic semiconductors doped with magnetic transition metals. The recently discovered DMS material (Ba1-xKx)(Zn1-yMny)(2)As-2 offers a unique and versatile control of the Curie temperature T-C 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 T-C. 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.

【 授权许可】

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