Electrical control of a Kondo spin screening cloud

TL;DR

This paper demonstrates the engineering and control of the Kondo cloud deformation using a quantum box, revealing insights into quantum interference effects and entanglement in strongly correlated electron systems.

Contribution

It introduces a method to manipulate the Kondo cloud via a quantum box, enabling experimental exploration of deformed Kondo clouds influenced by modulated density of states.

Findings

Controlled the Kondo cloud deformation through quantum interference tuning.

Observed that the cloud shape is mainly altered outside the quantum box.

Provided a new platform for simulating strongly correlated systems.

Abstract

Quantitative analysis of quantum many-body systems, consisting of numerous itinerant electrons that interact with localized spins or electrons, is a long-standing issue. The Kondo cloud, a quantum many-body object of conduction electrons that screens a single localized spin, is the building block of such strongly correlated electronic systems. While quantitative analysis of the Kondo cloud associated with a single magnetic impurity is well established for uniform conduction electrons, the fundamental properties of a deformed Kondo cloud influenced by conduction electrons with a modulated density of states remain unsolved. Here we report engineering of the Kondo cloud deformation by confining a part of the cloud into a quantum box called the Kondo box that mimics realistic material systems. We demonstrate quantitative control of the Kondo cloud by developing a way of tuning quantum interference in the box and monitoring the Kondo entanglement. The temperature dependence of the entanglement reveals counterintuitively that the cloud shape is altered mainly outside the box although the quantum interference in the box is tuned. Our work provides a way to simulate various strongly correlated systems by integrating the Kondo cloud, which is not possible in the current theoretical framework.