Quantum materials:  A short review presentation to introduce the apprentice undergraduates on engineering quantum materials and related physics, exotic quantum physics led emerging properties of materials for future electronics. 

Moire Pattern in Quantum materials:  Engineering in two-dimensional Transition Metal Dichalcogenides (TMDs) by van-der walls (vdW) stacking results to form Moire heterostructures, which have recently attracted significant attention as a platform for engineering novel electronic and excitonic states at the nanoscale. The twist or lattice mismatch between the vdW stacked layers leads to a periodic modulation of the electronic band structure, creating a moire superlattice through quantum confinement led to the emergence of new electronic states, such as flat bands or topological edge states. These unconventional electronic properties can be harnessed for next-generation electronics in several ways. This presentation will provide a good insight into the complex interplay between the structural properties of the interface and the emergent electronic and excitonic properties of moire heterostructures through dynamical manipulation of moire heterostructures, as well as their potential applications in quantum electronics and nano-optoelectronics.

The 'Scotch-tape method', which was first utilized to create monolayer graphene, involves the application of a sticky tape onto a layered material and its subsequent peeling off to obtain flakes consisting of a small number of layers. These flakes can be transferred onto a substrate for further study. However, this process yields mostly multilayer flakes, with little control over their size and shape. Although the monolayer yield is low, the quality of the monolayers produced is exceptional due to the absence of chemical processing and the reasonable size of the monolayer flakes (from a few microns up to ~100 microns). This method is also applicable to all van der Waals materials. As a result, mechanical exfoliation remains a popular technique for lab-based research but is not suitable for scaling up for use in new technologies.

Learn about the basics of 2D materials:

2D Materials: An Introduction to Two-Dimensional Materials

Physica Scripta 2012(T146):014006

DOI: 10.1088/0031-8949/2012/T146/014006

The atomic force microscope (AFM) is a specific type of scanning probe microscope (SPM) that is capable of measuring local properties, such as height, friction, and magnetism using a probe. The SPM is designed to acquire an image by scanning the probe over a small area of the sample, simultaneously measuring the local property being investigated.

We perform topography measurements by contact/noncontact atomic force microscopy are subject to residual electrostatic forces using a Kelvin probe force microscopy method with active compensation of electrostatic forces.

[AFM, PFM, STM]

Read, how AFM works: https://nanoscience.gatech.edu/zlwang/research/afm.html

Phys. Rev. Lett. 91, 266101, 2003, https://doi.org/10.1103/PhysRevLett.91.266101

Nanomaterials 2020, 10(4), 803; https://doi.org/10.3390/nano10040803

InfoMat. 2022;4:e12310, https://doi.org/10.1002/inf2.12310

Scanning Electron Microscopy (SEM) is a technique that can be used to analyze Quantum Moire Materials by using a focused beam of electrons to generate high-resolution images of the material's surface, revealing its topography and structural features. In Quantum Moire Materials, SEM can be particularly useful in identifying the presence of Moire patterns, which arise from the superposition of two-dimensional lattices. The technique can also provide insights into the material's electronic properties by mapping its local density of states. SEM can be used to visualize strain effects in materials by observing changes in their surface topography. The technique can reveal features such as wrinkles, ridges, and cracks, which arise from the local deformation of the material due to strain. Additionally, SEM can be used in combination with other techniques, such as micro-Raman spectroscopy, to investigate the influence of strain on the material's electronic and vibrational properties.

Nat. Nanotechnol. 15, 580–584 (2020). https://doi.org/10.1038/s41565-020-0708-3

Nat. Mater. 20, 480–487 (2021). https://doi.org/10.1038/s41563-020-00873-5

VESTA, a 3D visualization system for crystallographic studies and electronic state calculations, incorporates exclusively features such as external crystal morphology drawing, superimposing multiple structural models and densities, Voronoi tessellation integration, undo and redo operations, and performance improvements

Get this: https://jp-minerals.org/vesta/en/download.html

              http://www.jp-minerals.org/vesta/en/features.html 

J. Appl. Cryst. (2011). 44, 1272-1276

https://doi.org/10.1107/S0021889811038970

Aflow is a software framework for high-throughput calculation of crystal structure properties of alloys, intermetallics, and inorganic compounds, available with geometric and electronic structure analysis and manipulation tools for online operation at aflowlib.org, providing a powerful tool for quantum computational materials discovery and characterization.

AFLOW-Online, The AFLOW Prototype Encyclopedia, ALOW ML, AFLOW Convex HULL 

Get it: https://aflowlib.org/

Computational Materials Science, 58, 2012, 218-226, https://doi.org/10.1016/j.commatsci.2012.02.005 

Band structure diagram paths based on crystallography: This tool presents an algorithm for systematic and automatic calculations of electronic band structure by categorizing points in reciprocal space according to their symmetry, providing recommended band paths, and labeling points without conflict with the crystallographic convention, with an open-source implementation in SeeK-path python code and a free online service available at materialscloud.org to compute and visualize the first Brillouin zone and suggested band paths for any crystal structure.

Get it: https://tools.materialscloud.org/seekpath/

Comp. Mat. Sci. 128, 140 (2017). DOI: 10.1016/j.commatsci.2016.10.015  

CASTEP is a comprehensive materials modelling code that employs a first-principles quantum mechanical description of electrons and nuclei, utilizing the plane-wave basis set and pseudopotentials. 

All calculations are categorized as:

Hamiltonians, Structural methods, Molecular Dynamics, Vibrational Spectroscopy, Dielectric Properties, Solid-state NMR spectroscopy, Optical and other Spectroscopies, Electronic properties, Pseudopotentials, Electronic Solvers, Elastic Properties

Get it: http://www.castep.org/CASTEP/GettingCASTEP

J. Phys.: Condens. Matter,14, 2717, 2002, DOI 10.1088/0953-8984/14/11/301

The Vienna Ab initio Simulation Package (VASP) is a program for atomic-scale materials modeling, offering electronic structure calculations and quantum-mechanical molecular dynamics using DFT or HF approximation with hybrid functionals, Green's functions methods, and many-body perturbation theory. VASP expresses central quantities in plane wave basis sets and uses norm-conserving or ultrasoft pseudopotentials, or the projector-augmented-wave method to describe interactions between electrons and ions

Get it: https://www.vasp.at/info/about/;

            https://www.vasp.at/sign_in/registration_form/

            https://www.vasp.at/info/resource/

    https://www.vasp.at/wiki/index.php/The_VASP_Manual

Journal of Computational Chemistry, 29(13), 2044–2078. https://doi.org/10.1002/jcc.21057

*Licensed by Professor Alamgir Kabir, University of Dhaka, Bangladesh

Quantum ESPRESSO is an integrated suite of Open-Source computer codes for electronic-structure calculations and materials modeling at the nanoscale. It is based on density-functional theory, plane waves, and pseudopotentials.

Get it: https://www.quantum-espresso.org/download-page/ 

J. Phys.: Condens. Matter, 21, 395502, 2009, DOI 10.1088/0953-8984/21/39/395502

MATLAB is a proprietary numeric computing environment and multi-paradigm programming language developed by MathWorks, enabling matrix manipulations, function and data plotting, algorithm implementation, user interface creation, and interfacing with other languages, and also provides access to symbolic computing abilities via MuPAD symbolic engine and graphical multi-domain simulation and model-based design for dynamic and embedded systems via Simulink.

Get it: https://matlab.mathworks.com/ 

J. Phys.: Conf. Ser. 490, 012053, 2014, DOI 10.1088/1742-6596/490/1/012053

Proceedings of the ACM on Programming Languages, 4, HOPL, 81, 1–67, https://doi.org/10.1145/3386331