Heterostructures and Artificial Atoms from Quantum Matter

Heterostructures of quantum matter are particularly interesting systems. Quantum matter is defined by quantum effects that generate phenomena that surpass incoherent or mean-field behavior, and often are collective and emergent. Canonical quantum materials are the heavy-fermion compounds, the high-T_{c} cuprates, the iridates, correlated organic compounds, and the iron pnictides.

Unprecedented effects can occur if quantum materials are stacked, packed in quantum wells, brought into contact at interfaces, or altered by control parameters such as strain and electric fields imposed by gates. The phenomena thus induced are unforeseeable in their breadth and complexity.

In a recent review article, we provide an overview of this young scientific field and shed light on the enormous possibilities it may generate [1].

In a further review, we consider zero-dimensional electron systems, also known as quantum dots, from quantum matter [2].

The electron system of a quantum dot is described by a coherent many-body wave function with one macroscopic phase. Because of the shell structure of the electron states and their coherency across the dots, quantum dots are appropriately described as ‘artificial atoms’. We anticipate remarkable scientific advances and possibly important applications of these artificial atoms made from functional quantum materials.

With our recent experimental progress in patterning and contacting of oxide two-dimensional electron systems [3], we are now able to explore the surprising properties of complex-oxide artificial atoms and of molecules or even of solids assembled from them.