Electronic Structure of a Graphene-like Artificial Crystal of NdNiO3

Arab, Arian and Liu, Xiaoran and Koeksal, Okan and Yang, Weibing and Chandrasena, Ravini U and Middey, Srimanta and Kareev, Mikhail and Kumar, Siddharth and Husanu, Marius Adrian and Yang, Zhenzhong and Gu, Lin and Strocov, Vladimir N and Lee, Tien Lin and Minar, Jan and Pentcheva, Rossitza and Chakhalian, Jak and Gray, Alexander X (2019) Electronic Structure of a Graphene-like Artificial Crystal of NdNiO3. In: NANO LETTERS, 19 (11). pp. 8311-8317.

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Abstract

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 NdNiO3 confined between two 4-unit cell-thick layers of insulating LaAlO3. 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 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.

Item Type:	Journal Article
Publication:	NANO LETTERS
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copyright of this article belongs to AMER CHEMICAL SOC
Keywords:	Strongly correlated oxides; soft X-ray angle-resolved photoelectron spectroscopy; hard X-ray photoelectron spectroscopy
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	16 Dec 2019 10:27
Last Modified:	16 Dec 2019 10:27
URI:	http://eprints.iisc.ac.in/id/eprint/64063

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