Atomic Tunneling from a STM/AFM tip: Dissipative Quantum Effects from Phonons

TL;DR

This paper investigates how phonons strongly influence atomic tunneling between surfaces, revealing ohmic coupling effects and proposing experiments to observe macroscopic quantum coherence phenomena similar to SQUIDs.

Contribution

It demonstrates the first example of ohmic phonon coupling in a two-state system and suggests experimental setups to test quantum tunneling theories.

Findings

Phonons cause strong, qualitatively different tunneling behavior.

Proposes an STM-based experiment to observe quantum coherence effects.

Establishes a link between atomic tunneling and macroscopic quantum phenomena.

Abstract

We study the effects of phonons on the tunneling of an atom between two surfaces. In contrast to an atom tunneling in the bulk, the phonons couple very strongly, and qualitatively change the tunneling behavior. This is the first example of {\it ohmic} coupling from phonons for a two-state system. We propose an experiment in which an atom tunnels from the tip of an STM, and show how its behavior would be similar to the Macroscopic Quantum Coherence behavior predicted for SQUIDS. The ability to tune and calculate many parameters would lead to detailed tests of the standard theories. (For a general intro to this work on the on the World-Wide-Web: http://www.lassp.cornell.edu. Click on ``Entertaining Science Done Here'' and ``Quantum Tunneling of Atoms'')