Gd2Te3: an antiferromagnetic semimetal
Abstract
We report high-precision magnetization ([ image ]), magnetic susceptibility ([ image ]), specific heat (Cp (T, H)) and 'zero-field' electrical resistivity, [ image ], data taken on Gd2Te3 single crystal over wide ranges of temperature and magnetic field (H), with either [ image ]-axis or [ image ]-plane. [ image ] and [ image ] unambiguously establish that the b-axis is the easy direction of magnetization whereas any direction in the ac-plane is a hard direction. The [ image ]-type anomaly in 'zero-field' specific heat, Cp (T, H = 0), and an abrupt drop in [ image ] (characteristic of the paramagnetic (PM) — antiferromagnetic (AFM) phase transition) are observed at the Néel temperature, [ image ] K. [ image ] and Cp (T,H) clearly demonstrate that [ image ] shifts to lower temperatures with increasing H irrespective of whether H points in the easy or hard direction. When [ image ], the [ image ] isotherms at temperatures in the range 2.5 K [ image ] [ image ] K reveal the existence of a field-induced spin-flop (SF) transition at fields 4.0 T [ image ] [ image ] [ image ] 4.5 T. The first principles electronic band structure and density of states calculations, based on the density functional theory, correctly predict an AFM ground state (stabilized primarily by the 4f Gd3+ - 5p Te2-- 4f Gd3+ superexchange interactions) and the observed semi-metallic behavior for the Gd2Te3 compound. Moreover, these calculations yield the values [ image ] [ image ] for the ordered magnetic moment per Gd atom at T = 0, [ image ] mJ mol-1 K-2 for the Sommerfeld coefficient for the electronic specific heat contribution and [ image ] K for the Curie-Weiss temperature, respectively. These theoretical estimates conform well with the corresponding experimental values [ image ] [ image ], [ image ] mJ mol-1 K-2 and [ image ] K.
- Publication:
-
Journal of Physics Condensed Matter
- Pub Date:
- July 2019
- DOI:
- 10.1088/1361-648X/ab1570
- Bibcode:
- 2019JPCM...31B5802M
- Keywords:
-
- antiferromagnetsm;
- field-induced transition;
- topological semi-metal