Interplay of electronic, magnetic, and structural properties of GdB6 from first principles

Abstract

Gadolinium hexaboride (GdB 6 ) is a well known field emitter material that has been investigated for more than three decades. We perform a systematical density-functional theory (DFT) study of GdB 6 by using the generalized-gradient approximation and considering the electron interaction parameter U. The basic structural and electronic properties are carefully revised, as well as a strong U-value dependence in determining the antiferromagnetic (AFM) magnetic structures of Gd 4f electronic states. We found a small U (0~3eV) showing the most consistent experimental ground-state properties, which gives rise to a magnetic structure with a ground state of C-AFM and a second stable E-AFM. Moreover, we find the distortion modes of boron octahedron play an important role in the interaction between spin and lattice structures in this system. These results will deepen our understanding of the boron-based correlated rare earth compounds.

Role of spin-glass behavior in the formation of exotic magnetic states in GdB6

“…At the same time, the arrangement of pairs in each structure is clearly defined, as evidenced by the small width of the resonance line, and also slightly different from each other. Note, that the magnetic structure one of two lowest states E-AFM is consistent with neutron experiment results 27 , 28 , 60 . The absence of the satellites of the second structure may be caused by small volume of the corresponding domain as well as the complexity of the neutron experiment in GdB 6 27 , 28 .…”

“…It turns out that two types of magnetic orders, E-AFM and C-AFM (illustrated in Fig. 6 ), lay energetically close to each other in the wide range of the Coulomb repulsion parameter U with energy difference 0.6–1 meV (6–12 K) between them 60 . In its turn, the hysteretic properties of ESR absorption suggest the coexistence in AFM2 phase of domains with different types of magnetic structure.…”

“…Moreover, the value T N2 varies in the range 5–12 K in different experiments 23 – 26 , 29 , 33 , 59 . In the recent density functional calculations of GdB 6 the basic structural and electronic properties as well as the stability of different AFM structures were determined 60 . It turns out that two types of magnetic orders, E-AFM and C-AFM (illustrated in Fig.…”

First‐principles study of f‐orbital‐dependent band topology of topological rare earth hexaborides

“…The calculations with different spin values reveal the +3 charge state of Gd, with spin polarization pointing to magnetism in GdB 6 as per reported results. [ 11,35 ] We found that orbital polarization of GdB 6 is negligible compared to the spin polarization of 4 f orbitals from Gd atom.…”

“…[ 3 ] A first‐principles study and experimental analyses have shown evidence of antiferroquadrupolar ordering and crystal field splitting at band structure of CeB 6 . [ 3 ] Similarly, GdB 6 , [ 11 ] NdB 6 , [ 12,13 ] and PrB 6 [ 12 ] exhibited ferromagnetic ordering at low temperatures. [ 14 ] Semiconducting ferromagnetic ordering is observed at low temperatures in the semimetal EuB 6 and paramagnetic Fermi surfaces of PrB 6 , with antiferromagnetic ordering at low temperatures.…”