Controlling a Van Hove singularity and Fermi surface topology at a complex oxide heterostructure interface

• Published in: Nature communications Vol. 10; no. 1; pp. 5534 - 7
• Main Authors: Mori, Ryo, Marshall, Patrick B, Ahadi, Kaveh, Denlinger, Jonathan D, Stemmer, Susanne, Lanzara, Alessandra
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 04.12.2019; Nature Publishing Group UK; Nature Portfolio
• Subjects: Bandwidths; Emergence; Fermi surfaces; Gating; Heterostructures; Interfaces; Laboratories; Magnetism; MATERIALS SCIENCE; Occupancy; Organic chemistry; Quantum confinement; Saddle points; Singularities; Spectrum analysis; Superconductivity; Thickness; Topology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-13046-z

The emergence of saddle-point Van Hove singularities (VHSs) in the density of states, accompanied by a change in Fermi surface topology, Lifshitz transition, constitutes an ideal ground for the emergence of different electronic phenomena, such as superconductivity, pseudo-gap, magnetism, and density waves. However, in most materials the Fermi level, [Formula: see text], is too far from the VHS where the change of electronic topology takes place, making it difficult to reach with standard chemical doping or gating techniques. Here, we demonstrate that this scenario can be realized at the interface between a Mott insulator and a band insulator as a result of quantum confinement and correlation enhancement, and easily tuned by fine control of layer thickness and orbital occupancy. These results provide a tunable pathway for Fermi surface topology and VHS engineering of electronic phases.