Angle-resolved photoemission spectroscopy study of magnetic topological insulator candidates of Ce-doped Bi2-xCexSe3

초록

The electronic structures of the magnetic topological insulator candidates of Ce-substituted Bi2-xCexSe3 (x <= 0.12) have been investigated through angle-resolved photoemission spectroscopy (ARPES), soft X-ray absorption spectroscopy (XAS), and soft X-ray magnetic circular dichroism (XMCD) measurements on high-quality single crystals. Ce 3d XAS and XMCD measurements provide evidence that the substituted Ce ions in Bi2-xCexSe3 are trivalent and magnetic, confirming the purely magnetic effect of the Ce-substitution. ARPES measurements reveal the formation of an energy gap (Delta) for x>0, indicating that the finite Delta arises from the broken time-reversal symmetry due to the substituted magnetic Ce impurities.

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