Rare-earth-doped Bi2X3 (X = Se, Te) as candidates for magnetic topological insulators

초록

Electronic structures of rare-earth (R)-doped single crystals, which are promising candidates for magnetic topological insulators, have been investigated by employing soft X-ray absorption spectroscopy (XAS), soft X-ray magnetic circular dichroism (XMCD), and circular dichroism (CD) angle-resolved photoemission spectroscopy (ARPES). R XAS and XMCD measurements provide evidence that R ions are trivalent and magnetic, confirming that doped R ions have purely magnetic effects. ARPES measurements of show a finite energy gap for x>0, arising from the broken time-reversal symmetry due to magnetic R impurities. CD-ARPES measurements of reveal finite CD effects in the topological surface states. This work demonstrates that are magnetic topological insulators.

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