New Scanning Tunneling Microscopy Technique Enables Systematic Study of the Unique Electronic Transition from Graphite to Graphene

TL;DR

This paper introduces a novel electrostatic-manipulation STM technique that allows controlled study of the electronic transition from graphite to graphene, revealing a continuous structural and electronic change driven by vertical displacements.

Contribution

The study demonstrates a new STM method enabling systematic control of the graphite-to-graphene transition through electrostatic manipulation and detailed theoretical analysis.

Findings

Controlled transition from triangular to honeycomb lattice observed

Vertical displacement of 0.09 nm causes a shift from parabolic to linear bands

Electrostatic manipulation enables reversible and irreversible surface movements

Abstract

A series of measurements using a novel technique called electrostatic-manipulation scanning tunneling microscopy were performed on a highly-oriented pyrolytic graphite (HOPG) surface. The electrostatic interaction between the STM tip and the sample can be tuned to produce both reversible and irreversible large-scale vertical movement of the HOPG surface. Under this influence, atomic-resolution STM images reveal that a continuous electronic reconstruction transition from a triangular symmetry, where only alternate atoms are imaged, to a honeycomb structure can be systematically controlled. First-principles calculations reveal that this transition can be related to vertical displacements of the top layer of graphite relative to the bulk. Detailed analysis of the band structure predicts that a transition from parabolic to linear bands occurs after a 0.09 nm displacement of the top layer.