Electronic structure of the high-mobility two-dimensional antiferromagnetic metal $\mathrm{Gd}{\mathrm{Te}}_3$

The newfound two-dimensional antiferromagnetic $\mathrm{Gd}{\mathrm{Te}}_3$ has great potential in novel magnetic twistronic and spintronic devices because it has the highest carrier mobility among all known layered magnetic materials. Here, we used high-resolution angle-resolved photoemission spectroscopy to investigate its Fermi-surface topology and low-lying electronic band structure. The Fermi surface is partially gapped by charge-density waves below the transition temperature. Very steep and nearly linear band dispersion near the Fermi energy contributes to the high carrier mobility in $\mathrm{Gd}{\mathrm{Te}}_3$. We find that the scattering rate of the quasiparticle increases linearly as a function of binding energy within a wide energy range, indicating that $\mathrm{Gd}{\mathrm{Te}}_3$ is a non-Fermi-liquid metal. Our results in this paper provide a fundamental understanding of this layered antiferromagnetic material to guide future studies on it.

Figure 1

(a) The crystal structure of $\mathrm{Gd}{\mathrm{Te}}_3$. (b) Powder x-ray diffraction pattern of cleaved $\mathrm{Gd}{\mathrm{Te}}_3$ single crystals; inset shows the optical image of a typical single crystal sample at the millimeter scale. (c) Temperature dependence of the in-plane resistivity of the sample. The inset is the in-plane resistivity under transverse magnetic fields of 0 and 3 T in the low-temperature range. (d) Temperature-dependent magnetic susceptibility of a bulk $\mathrm{Gd}{\mathrm{Te}}_3$ crystal; inset illustrates the temperature dependence of the difference between both susceptibilities (${\chi }_d={\chi }_{ab}-{\chi }_c$).

Figure 2

(a) Sketch of 3D BZ and 2D BZ, which result from the 3D unit cell and the Te square-net sheet, respectively. The lower right panel shows a schematic of the dispersion for folded band and bilayer splitting. (b) ARPES FS map obtained by integration of spectral weight in a 10 meV window below $E_F$, taken with photon energy of 95 eV and at 15 K. The arrow indicates the wave vector of the CDW. (c) Photoemission integrated intensity plot at binding energy of 0.2 eV within a 10 meV window. (d) Band dispersion near $E_F$ measured with the photon energy of 33 eV. (e) The corresponding second derivative image of panel (d) with respect to the momentum.

Figure 3

Band dispersion near $E_F$ taken along $k_y$ at $k_x=0.26{\AA }^{-1}$ and with the photon energy of 33 eV. (a) Second derivative image and its corresponding MDCs. (b) A linear fit was used to evaluate its Fermi velocity. The red MDC line is recorded at $E_F$. (c) Extracted full width of half maximum of the main band in momentum by using Lorentz fitting.

Figure 4

Schematic of rare-earth antiferromagnetic superex- change-like and RKKY interactions.