Quantum information science and engineering (QISE) which entails generation, control and manipulation of individual quantum mechanical states together with nanotechnology have dominated condensed matter physics and materials science research in the 21st century. Solid state devices for QISE have, to this point, predominantly been designed with bulk material as their constituents. In this review, we consider how nanomaterials or low-dimensional materials i.e. materials with intrinsic quantum confinement -may offer inherent advantages over conventional materials for QISE. We identify the materials challenges for specific types of qubits, and we identify how emerging nanomaterials may overcome these challenges. Challenges for and progress towards nanomaterials-based quantum devices are identified. We aim to help close the gap between the nanotechnology and quantum information communities and inspire research that will lead to next-generation quantum devices for scalable and practical quantum applications.

A multistep phase sequence following the crystallization of amorphous Al2O3 via solid-phase epitaxy (SPE) points to methods to create low-defect-density thin films of the metastable cubic γ-Al2O3 polymorph. An amorphous Al2O3 thin film on a (0001) α-Al2O3 sapphire substrate initially transforms upon heating to form epitaxial γ-Al2O3, followed by a transformation to monoclinic θ-Al2O3, and eventually to α-Al2O3. Epitaxial γ-Al2O3 layers with low mosaic widths in X-ray rocking curves can be formed via SPE by crystallizing the γ-Al2O3 phase from amorphous Al2O3 and avoiding the microstructural inhomogeneity arising from the spatially inhomogeneous transformation to θ-Al2O3. A complementary molecular dynamics (MD) simulation indicates that the amorphous layer and γ-Al2O3 have similar Al coordination geometry, suggesting that γ-Al2O3 forms in part because it involves the minimum rearrangement of the initially amorphous configuration. The lattice parameters of γ-Al2O3 are consistent with a structure in which the majority of the Al vacancies in the spinel structure occupy sites with tetrahedral coordination, consistent with the MD results. The formation of Al vacancies at tetrahedral spinel sites in epitaxial γ-Al2O3 can minimize the epitaxial elastic deformation of γ-Al2O3 during crystallization.

Metamaterials and metasurfaces operating in the visible and near‐infrared (NIR) offer a promising route towards next‐generation photodetectors and devices for solar energy harvesting. While numerous metamaterials and metasurfaces using metals and semiconductors have been demonstrated, semimetals‐based metasurfaces in the vis‐NIR range are notably missing. This work experimentally demonstrates a broadband metasurface superabsorber based on large area, semimetallic, van der Waals platinum diselenide (PtSe2) thin films in agreement with electromagnetic simulations. The results show that PtSe2 is an ultrathin and scalable semimetal that concurrently possesses high index and high extinction across the vis‐NIR range. Consequently, the thin‐film PtSe2 on a reflector separated by a dielectric spacer can absorb >85% for the unpatterned case and ≈97% for the optimized 2D metasurface in the 400–900 nm range making it one of the strongest and thinnest broadband perfect absorbers to date. The results present a scalable approach to photodetection and solar energy harvesting, demonstrating the practical utility of high index, high extinction semimetals for nanoscale optics.

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materials that are freestanding either at a stage in their fabrication, in their final state, or both. [1] NMs with thicknesses in the range of a few nanometers to a few hundred nanometers can be isolated from their substrates through synthesis and processing techniques that have become established in the last 20 years. [1][2][3][4][5] The lateral dimensions of NMs are at least two orders of magnitude larger than their thickness, making them a distinctive platform from 0D, 1D, and bulk materials. [6] NMs enable a vast range of possibilities, including i) the capability to subject materials to elastic strain fields with magnitudes or geometries that are not realizable in bulk materials or by direct growth; [7][8][9] ii) unique and rapid characterization of materials properties and kinetic processes; [10,11] iii) heterogeneous integration of materials via controlled transfer, including, into environments in which the NM materials would be otherwise inaccessible via synthesis; [12,13] iv) 3D structures that can be processed in parallel on large-area substrates and can find use in several applications. [14][15][16][17][18] The scope of applications and phenomena that benefit from NMs can be extended to a new spectrum of materials Reconfiguration of amorphous complex oxides provides a readily controllable source of stress that can be leveraged in nanoscale assembly to access a broad range of 3D geometries and hybrid materials. An amorphous SrTiO 3 layer on a Si:B/Si 1−x Ge x :B heterostructure is reconfigured at the atomic scale upon heating, exhibiting a change in volume of ≈2% and accompanying biaxial stress. The Si:B/Si 1−x Ge x :B bilayer is fabricated by molecular beam epitaxy, followed by sputter deposition of SrTiO 3 at room temperature. The processes yield a hybrid oxide/semiconductor nanomembrane. Upon release from the substrate, the nanomembrane rolls up and has a curvature determined by the stress in the epitaxially grown Si:B/Si 1−x Ge x :B heterostructure. Heating to 600 °C leads to a decrease of the radius of curvature consistent with the development of a large compressive biaxial stress during the reconfiguration of SrTiO 3 . The control of stresses via post-deposition processing provides a new route to the assembly of complex-oxide-based heterostructures in 3D geometry. The reconfiguration of metastable mechanical stressors enables i) synthesis of various types of strained superlattice structures that cannot be fabricated by direct growth and ii) technologies based on strain engineering of complex oxides via highly scalable lithographic processes and on large-area semiconductor substrates.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202105424.