Strongly Correlated Electrons on a Silicon Surface: Theory of a Mott Insulator

TL;DR

This paper theoretically demonstrates that potassium-covered Si(111)-B surface is a Mott insulator, contradicting band theory but aligning with experiments, by combining density-functional calculations and many-body Hamiltonian analysis.

Contribution

It provides a detailed theoretical analysis showing the Mott insulating state on a silicon surface using advanced computational methods.

Findings

The surface is a Mott insulator, not predicted by band theory.

A Brinkman-Rice transition is identified at a critical interaction strength.

Calculated interaction strength exceeds the critical value for insulating behavior.

Abstract

We demonstrate theoretically that the electronic ground state of the potassium-covered Si(111)-B surface is a Mott insulator, explicitly contradicting band theory but in good agreement with recent experiments. We determine the physical structure by standard density-functional methods, and obtain the electronic ground state by exact diagonalization of a many-body Hamiltonian. The many-body conductivity reveals a Brinkman-Rice metal-insulator transition at a critical interaction strength; the calculated interaction strength is well above this critical value.