Indication of exchange interaction induced spin splitting in unoccupied electronic states of the high- TC ferromagnet ( Cr0.35Sb0.65<mml:…

We study the high Curie temperature ferromagnet (Cr0.35Sb0.65)₂Te₃ (TC=1920.16em0exK), using T-dependent x-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism (XMCD), and angle-resolved photoemission spectroscopy (ARPES). The T-dependent (25--220 K) XAS-XMCD evolution of Cr0.16em0ex3d and Te0.16em0ex5p unoccupied site- and orbital-projected states shows a systematic modification, which we interpret as due to spin-splitting below TC. The T-dependent XMCD intensity and leading-edge spin-sensitive shifts γₑₓₚₜ(T) follow bulk magnetization. ARPES measurements with hν=784pt0exeV show a metallic state with Sb $5p$ band dispersions at and near Fermi level (EF), consistent with bulk band-structure calculations for (Cr0.33Sb0.67)₂Te₃. However, surface-sensitive ARPES with hν=8.40.16em0exeV above and below TC show linear band dispersions just below EF, suggesting a remnant of Dirac-type dispersions. Assuming the linear dispersion survives above EF, it implies a topologically trivial ferromagnet as the estimated Dirac point energy lies above the largest γₑₓₚₜ4pt0ex(T=250.16em0exK). The Cr0.16em0ex3d XAS-XMCD spectra can be simulated by charge transfer multiplet cluster model calculations with an exchange field Hₑₓ which quantitatively reproduces the experimental XMCD. At T=250.16em0exK, the required exchange field Hₑₓ of ~480.16em0exT corresponds to a Zeeman energy ζ=2.80.16em0exmeV0.16em0ex<4pt0exTC=1920.16em0exK (= 16.5 meV) γₑₓₚₜ~1400.16em0exmeV. The results indicate the role of Cr0.16em0ex3d exchange interactions in causing spin-sensitive shifts in Cr0.16em0ex3d states, and inducing comparable spin-sensitive shifts via hybridization in Te0.16em0ex5p states of (Cr0.35Sb0.65)₂Te₃.