Electronic Structures of Cr-Intercalated ZrTe₂Revealed by Angle-Resolved Photoemission Spectroscopy

The intercalation of transition metal atoms into the van der Waals gap of the layered transition metal dichalcogenides (TMDCs) results in modulations of electronic structures and transport properties of the host materials. In order to reveal the physical mechanism of intercalation, it is essential to elucidate the band structures, especially near the Fermi level, which contributes significantly to physical properties of a solid. Taking advantage of angle-resolved photoemission spectroscopy (ARPES), we studied how Cr intercalation modifies the electronic structures of the pristine ZrTe2 in the intercalated compound Cr0.4ZrTe2. By comparing with the semimetal band structures of ZrTe2, we found a nonrigid shift in the band dispersions of Cr0.4ZrTe2, in which an indirect gap opens between the valence and conduction bands with only electron-type carriers contributing to the electronic states at the Fermi level. Moreover, additional electronic states emerge below the bottom of the conduction band at M and exhibit a strong temperature-dependent behavior. Our studies show that the intercalation of atoms in van der Waals crystals could regulate the inherent band dispersions of the host materials and induce new physical properties.