Polarization transitions in Quantum Dot Quantum Well Arrays

TL;DR

This paper investigates polarization phase transitions in 2D and 3D arrays of quantum-dot quantum wells, revealing classical and quantum groundstates, including antiferroelectric and frustrated states, with implications for experimental detection.

Contribution

It provides a detailed analysis of polarization transitions in nano-structured arrays, highlighting differences between classical and quantum groundstates and the effects of lattice geometry.

Findings

Square arrays exhibit classical AFE groundstates.

Quantum arrays transition from uniform to AFE states.

FCC lattices show layered polarization with alternating directions.

Abstract

With the improvement in fabrication techniques it is now possible to produce atom-like semiconductor structures with unique electronic properties. This makes possible periodic arrays of nano-structures in which the Coulomb interaction, polarizability, and tunneling may all be varied. We study the collective properties of 2D arrays and 3D face centered cubic lattices of singly-charged nano-spherical shells, sometimes called `quantum-dot quantum wells' or `core-shell quantum dots.' We find that for square arrays, the classical groundstate is an Ising anti-ferroelectret (AFE), while the quantum groundstate undergoes a transition from a uniform state to an AFE. The triangular lattice, in contrast, displays properties characteristic of frustration. Three dimensional face-centered cubic lattices polarize in planes, with each layer alternating in direction. We discuss the possible experimental signals of these transitions.