Article
Materials Science, Multidisciplinary
Nikolay Prokof'ev, Boris Svistunov
Summary: We report a breakthrough development in solving a broad class of polaron problems with highly nonlinear electron-phonon coupling using a Monte Carlo technique in the coordinate representation. This technique simplifies the models with dispersionless phonons and sheds light on the qualitative and quantitative effects of the "standard" linear displacement-modulated hopping model.
Article
Materials Science, Multidisciplinary
Xubo Zhu, Wanqi Jie, Yanqiu Lyu, Zhenyu Peng, Xiancun Cao, Mo Li, Guansheng Yao, Lixue Zhang
Summary: When the operating temperature rapidly decreases from room temperature to 77 K, the band structure of InAs/GaSb superlattices device is affected by thermal strain. Two strain models of the device with and without substrate were designed and fabricated, with the thickness of silicon ROIC identified as the main factor affecting band structure. A model with Al2O3 substrate and silicon ROIC thickness below 500 µm was recommended for having less bandgap deviation and the measured PL spectrum and spectral response confirmed the simulation results.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Physics, Multidisciplinary
Tran Cong Phong, Vo T. T. Vi, Le T. T. Phuong
Summary: The optical conductivity of strained monolayer /312-borophene was studied using the Kubo formula and the five-band tight-binding method. Strain-induced modifications in the hopping energy of electrons were found to affect the electronic dispersion and optical conductivity. Tensile strain caused mass generation in inherent massless Dirac fermions, while compressive strain doubled the number of inherent triplet fermions. We also observed a redshift spectrum in the strain-induced longitudinal optical conductivity, and a blueshift spectrum in the transverse/Hall optical conductivity. These findings highlight the tunability of electronic properties and optoelectronic applications of /312-borophene through strain engineering.
Article
Physics, Condensed Matter
Feng-Lin Shyu
Summary: Band structures of armchair graphene nanoribbons (AGNRs) under crossed external fields are calculated using the tight-binding model. The results show that magnetic field and electric field both have significant effects on the band structures, further demonstrating the complex characteristics of these effects on plasmon spectra and reflectance spectra.
PHYSICA B-CONDENSED MATTER
(2021)
Article
Chemistry, Physical
Kim Lopez-Guell, Nicolas Forrer, Xavier Cartoixa, Ilaria Zardo, Riccardo Rurali
Summary: Crystal phase engineering can alter phonon transport, and twinning superlattices exhibit two transportation mechanisms depending on interface number and spacing.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Kim Lopez-Guell, Nicolas Forrer, Xavier Cartoixa, Ilaria Zardo, Riccardo Rurali
Summary: Crystal phase engineering allows for the manipulation of phonon transport in periodic nanostructures, such as twinning superlattices. This study focuses on GaAs and InAs twinning superlattices and identifies two distinct transport regimes, one where each interface behaves as an independent scatterer and another where a segment with closely spaced interfaces acts as a metamaterial with its own thermal properties.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Alireza Mostafaei, Ebrahim Heidari Semiromi
Summary: This study focuses on the electronic structure of a class of MXene monolayers named M2XT2, and provides an accurate description using a parameterized minimal tight-binding model. The results show that this model effectively describes the electronic structure of these materials over a wide energy range.
Article
Physics, Multidisciplinary
N. B. Melnikov, B. Reser
Summary: The tight-binding method, initially designed for crystals with two atoms per unit cell, is extended to crystals with multiple atoms per unit cell. A technique based on group theory is introduced to express the matrix components of the tight-binding Hamiltonian in terms of independent parameters. This approach is demonstrated by obtaining an analytical form of the low-dimensional effective Hamiltonian for the conduction band of 2H-TaSe2 with quasi 2D hexagonal crystal structure.
Article
Materials Science, Multidisciplinary
Hamze Mousavi, Moein Asshabi, Samira Jalilvand, Jabbar Khodadadi
Summary: In this theoretical study, the density of states (DOS), electronic heat capacity (EHC), and Pauli magnetic susceptibility (PMS) of graphdiyne system under different strain values were calculated using the nearest neighbor tight-binding model and Green's function technique. The results show that with increasing strain, the band gap near the Fermi level of graphdiyne increases monotonously. Additionally, intra-bandgaps and van-Hove singularities were observed in the DOS curves, leading to Schottky anomaly peaks in the EHC and crossovers in the PMS curves.
Article
Materials Science, Multidisciplinary
A. L. Rakhmanov, A. V. Rozhkov, A. O. Sboychakov
Summary: This study analytically and numerically investigates the electronic properties of a circular quantum dot made from AA-stacked bilayer graphene. The researchers observe a set of discrete dot radii where the low-energy electron states are degenerate with respect to the layer parity. They find that by analogy with the "magic angles" in twisted bilayer graphene, these radii are referred to as "magic". The researchers argue that this analogy can be useful for the theoretical description of the electronic properties of twisted bilayer graphene.
Article
Nanoscience & Nanotechnology
Vladimir Fedorov, Maxim Vinnichenko, Ratmir Ustimenko, Demid Kirilenko, Evgeny Pirogov, Alexander Pavlov, Roman Polozkov, Vladislav Sharov, Andrey Kaveev, Dmitry Miniv, Liliia Dvoretckaia, Dmitry Firsov, Alexey Mozharov, Ivan Mukhin
Summary: Crystal phase and strain engineering in epitaxial nanowire heterostructures can provide tunable functionality in nanoscale light emitters and photodetectors. In this study, the inhomogeneity of the InP shell thickness in InAs core-shell nanowires was found to affect the recombination mechanisms, as well as the emission energy. Temperature-dependent photoluminescence studies showed non-trivial temperature dependence, with radiative recombination mainly occurring in the regions with a thicker InP shell and a tensile strain in the InAs core.
ACS APPLIED NANO MATERIALS
(2023)
Article
Physics, Condensed Matter
Bing-Yang Feng, En-Jia Ye, Yun-Lei Sun
Summary: The spin-polarized edge-state transport properties in L-shaped zigzag MoS2 nanodevice were investigated, and it was found that the spin conductance is closely related to the atomic configuration on the edge of the nanodevice. The spin conductance can be modulated by external fields and the edge channels are affected by sublattice and spin mismatches. As a result, a 100% spin polarization is achieved. The modulation of spin-resolved edge-state and spin-filtering effects are revealed in real space, suggesting potential application in nanocircuits.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Yunhai Li, Zhen Zhan, Xueheng Kuang, Yonggang Li, Shengjun Yuan
Summary: TBPLaS is an open-source software package that uses tight-binding theory to accurately simulate physical systems with arbitrary geometry and dimensionality. It provides an intuitive Python API and Cython/Fortran extensions for efficient and flexible calculations. TBPLaS utilizes both exact diagonalization and the tight-binding propagation method (TBPM), achieving linear scaling in memory and CPU costs. It can calculate various properties of large tight-binding models, such as band structure, density of states, optical conductivity, and carrier mobility. The code is highly extendable and modular, allowing for easy implementation of other algorithms involving tight-binding Hamiltonians.
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Physics, Condensed Matter
Sake Wang, Hongyu Tian, Minglei Sun
Summary: We investigate the influence of strain on the valley-polarized transmission of graphene using wave-function matching and the non-equilibrium Green's function technique. Our results show that increasing the width of the strained region and adjusting the extensional strain in the armchair and zigzag directions can improve valley polarization and transmission. Shear strain, however, does not affect transmission or valley polarization. Additionally, we find that enhancing the smoothness of the strain barrier can enhance valley-polarized transmission. Our findings offer new insights for the construction of graphene-based valleytronic and quantum computing devices using strain alone.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Multidisciplinary Sciences
Paola S. Oviedo, Luis M. Baraldo, Alejandro Cadranel
Summary: This work investigates the concept of engineering differential wave function overlap between excited states within a molecular chromophore to control excited state wave function symmetries, which leads to differential orbital overlap and low-energy trajectories within the excited state surface. By exploring two donor-acceptor assemblies, it was found that visible light absorption can prepare excited states with different wave function symmetry, allowing for energy transfer and backelectron transfer. The presence of kinetic barriers prevents excited state equilibration, providing a strategy to avoid energy dissipation in energy conversion or photoredox catalytic schemes.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
