Magnetic Properties Controlled by Interstitial or Interlayer Cations in Iron Chalcogenides

Shan-Chang Tang; Ming-Cui Ding; Yu-Zhong Zhang

doi:10.1038/srep19031

paper

Magnetic Properties Controlled by Interstitial or Interlayer Cations in Iron Chalcogenides

arXiv:1603.04952 · doi:10.1038/srep19031

Abstract

By applying density functional theory calculations to iron chalcogenides, we find that magnetic order in Fe $_{1 + y}$ Te and magnetic instability at $(π, π)$ in K $_{y}$ Fe $_{2}$ Se $_{2}$ are controlled by interstitial and interlayer cations, respectively. While in Fe $_{1 + y}$ Te, magnetic phase transitions occur among collinear, exotic bicollinear and plaquette-ordered antiferronmagnetic states when the height of interstitial irons measured from iron plane or the concentration of interstitial irons is varied, the magnetic instability at $(π, π)$ which is believed to be responsible for the Cooper pairing in iron pnictides is significantly enhanced when $y$ is much smaller than $1$ in K $_{y}$ Fe $_{2}$ Se $_{2}$ . Our results indicate that, similar to iron pnictides, itinerant electrons play important roles in iron chalcogenides, even though the fluctuating local moments become larger.

8 pages, 5 figures