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

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Saddle-point Van Hove singularities (VHSs) in density of states, coupled with Lifshitz transitions, foster diverse electronic phenomena like superconductivity and magnetism.
• Achieving these states is challenging as the Fermi level is often too distant from VHSs for conventional tuning methods.

Purpose of the Study:

• To demonstrate a novel method for accessing and engineering Van Hove singularities (VHSs) and Fermi surface topology.
• To explore the potential for realizing exotic electronic phases through interface engineering.

Main Methods:

• Investigated the interface between a Mott insulator and a band insulator.
• Utilized quantum confinement and correlation enhancement effects.
• Controlled electronic properties by adjusting layer thickness and orbital occupancy.

Main Results:

• Successfully realized saddle-point Van Hove singularities (VHSs) and altered Fermi surface topology at the insulator interface.
• Demonstrated tunability of these electronic properties via precise control over material parameters.
• Established a pathway to engineer electronic phases through interface modification.

Conclusions:

• Interface engineering between Mott and band insulators offers a viable route to tune Fermi surface topology and Van Hove singularities (VHSs).
• This approach facilitates the exploration of novel electronic phenomena, overcoming limitations of traditional tuning techniques.