Structural, electronic and magnetic properties of TlFeSe2under high pressure
Hanxing Zhang1,2, Jing Zhao1,2, Caoping Niu1,2
1Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China.
Abstract:
The high-pressure (HP) properties of TlFeSe2are investigated based on the first-principles calculations combined with structure-searching method. The low-pressureC2/mphase will transform into the orthorhombicPnmaphase at 2 GPa, with 8% volume collapse, the insulator-metal transition and the bicollinear antiferromagnetic-to-nonmagnetic spin-crossover. At pressure higher than 8 GPa, the HPC2/mphase will become the ground state. BothPnmaphase and HPC2/mphase are constituted by one-dimensional chains of edge-sharing FeSe5tetragonal pyramids. Pressuring decrease the Se-Se bond length giving rise to the transition from [Se2]3-to [Se2]2-. Negative charge transfer causes the Fe2+with ∼2 μBmagnetic moment at ambient pressure and the nonmagnetic Fe1.5+at higher pressure. The Fermi surfaces of HP phases are also discussed.
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