Electronic Structure of a Graphene-like Artificial Crystal of NdNiO3
| Autor: | Tien-Lin Lee, Ravini U. Chandrasena, Zhenzhong Yang, Rossitza Pentcheva, Alexander X. Gray, Mikhail Kareev, Jan Minár, Xiaoran Liu, Marius-Adrian Husanu, Weibing Yang, Okan Köksal, Srimanta Middey, Vladimir N. Strocov, Arian Arab, Lin Gu, Siddharth Kumar, Jak Chakhalian |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Strongly Correlated Electrons (cond-mat.str-el) Graphene Mechanical Engineering FOS: Physical sciences Bioengineering Heterojunction 02 engineering and technology General Chemistry Electronic structure 021001 nanoscience & nanotechnology Condensed Matter Physics hard X-ray photoelectron spectroscopy soft X-ray angle-resolved photoelectron spectroscopy law.invention Crystal Condensed Matter - Strongly Correlated Electrons Condensed Matter::Materials Science Strongly correlated oxides Chemical physics law Quantum state General Materials Science 0210 nano-technology |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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