Electronic structure of a graphene-like artificial crystal of $NdNiO_3$
| Title: | Electronic structure of a graphene-like artificial crystal of $NdNiO_3$ |
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| Authors: | Arab, Arian, Liu, Xiaoran, Köksal, O., Yang, W., Chandrasena, R. U., Middey, S., Kareev, M., Kumar, S., Husanu, M. -A., Yang, Z., Gu, L., Strocov, V. N., Lee, T. -L., Minár, J., Pentcheva, R., Chakhalian, J., Gray, A. X. |
| Publication Year: | 2019 |
| Collection: | Condensed Matter |
| Subject Terms: | Condensed Matter - Strongly Correlated Electrons |
| More Details: | Artificial complex-oxide heterostructures containing ultrathin buried layers grown along the pseudocubic [111] direction have been predicted to host a plethora of exotic quantum states arising from the graphene-like lattice geometry and the interplay between strong electronic correlations and band topology. To date, however, electronic-structural investigations of such atomic layers remain an immense challenge due to the shortcomings of conventional surface-sensitive probes, with typical information depths of a few Angstroms. Here, we use a combination of bulk-sensitive soft x-ray angle-resolved photoelectron spectroscopy (SX-ARPES), hard x-ray photoelectron spectroscopy (HAXPES) and state-of-the-art first-principles calculations to demonstrate a direct and robust method for extracting momentum-resolved and angle-integrated valence-band electronic structure of an ultrathin buckled graphene-like layer of $NdNiO_3$ confined between two 4-unit cell-thick layers of insulating $LaAlO_3$. The momentum-resolved dispersion of the buried Ni d states near the Fermi level obtained via SX-ARPES is in excellent agreement with the first-principles calculations and establishes the realization of an antiferro-orbital order in this artificial lattice. The HAXPES measurements reveal the presence of a valence-band (VB) bandgap of 265 meV. Our findings open a promising avenue for designing and investigating quantum states of matter with exotic order and topology in a few buried layers. |
| Document Type: | Working Paper |
| DOI: | 10.1021/acs.nanolett.9b03962 |
| Access URL: | http://arxiv.org/abs/1905.11441 |
| Accession Number: | edsarx.1905.11441 |
| Database: | arXiv |
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