Many-body perturbation theory study of type-II InAs/GaSb superlattices within the GW approximation

Taghipour, Zahra; Shojaee, Ezad; Krishna, S.

doi:10.1088/1361-648x/aacdce

Cited by 10 publications

(6 citation statements)

References 38 publications

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“…Hybrid functionals and GW produce improved band gaps for bulk materials [122,[138][139][140][141][142][143]. For surfaces and interfaces, hybrid functionals and the GW method provide a reliable description of the electronic structure, including band gaps [144][145][146][147] and band offsets [148][149][150][151][152][153]. In addition, GW has been used to study the behavior of surface/interface states [151].…”

Section: Choice Of Exchange-correlation Functionalmentioning

confidence: 99%

Best practices for first-principles simulations of epitaxial inorganic interfaces

Dardzinski

Moayedpour

et al. 2022

J. Phys.: Condens. Matter

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At an interface between two materials physical properties and functionalities may be achieved, which would not exist in either material alone. Epitaxial inorganic interfaces are at the heart of semiconductor, spintronic, and quantum devices. First principles simulations based on density functional theory (DFT) can help elucidate the electronic and magnetic properties of interfaces and relate them to the structure and composition at the atomistic scale. Furthermore, DFT simulations can predict the structure and properties of candidate interfaces and guide experimental efforts in promising directions. However, DFT simulations of interfaces can be technically elaborate and computationally expensive. To help researchers embarking on such simulations, this review covers best practices for first principles simulations of epitaxial inorganic interfaces, including DFT methods, interface model construction, interface structure prediction, and analysis and visualization tools.

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Section: Choice Of Exchange-correlation Functionalmentioning

confidence: 99%

Best practices for first-principles simulations of epitaxial inorganic interfaces

Dardzinski

Moayedpour

et al. 2022

J. Phys.: Condens. Matter

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“…The energy band structure of T2SLs can be calculated using various theoretical approaches like the density functional theory (DFT) [44], the empirical tightbinding method [35,45,46], the empirical pseudopotential method [47,48], many-body perturbation theory [49] and the k.p perturbation method [37]. For this study, we use the k.p technique with the envelope function approximation (EFA) [24,50,51] since it overcomes the computational limitations of first-principles methods.…”

Section: A Electronic Band Structurementioning

confidence: 99%

Advancing carrier transport models for InAs/GaSb type-II superlattice MWIR photodetectors

Kumar¹,

Mandia²,

Singh³

et al. 2023

Preprint

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In order to provide the best possible performance, modern infrared photodetector designs necessitate extremely precise modeling of the superlattice absorber region. We advance the Rode's method for the Boltzmann transport equation in conjunction with the k.p band structure and the envelope function approximation for a detailed computation of the carrier mobility and conductivity of layered type-II superlattice structures, using which, we unravel two crucial insights. First, the significance of both elastic and inelastic scattering mechanisms, particularly the influence of the interface roughness and polar optical phonon scattering mechanisms in technologically relevant superlattice structures. Second, that the structure-specific Hall mobility and Hall scattering factor reveals that temperature and carrier concentrations significantly affect the Hall scattering factor, which deviates significantly from unity even for small magnetic fields. This reinforces the caution that should be exercised when employing the Hall scattering factor in experimental estimations of drift mobilities and carrier concentrations. Our research hence offers a comprehensive microscopic understanding of carrier dynamics in such technologically relevant superlattices. Our models also provide highly accurate and precise transport parameters beyond the relaxation time approximation and thereby paving the way to develop physics-based device modules for mid-wavelength infrared photodetectors.

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“…Others have used hybrid functionals, which mitigate the effect of SIE by including a fraction of exact exchange [49]. An alternative approach, which has been used to obtain more accurate band gaps for InAs/GaSb is many-body perturbation theory within the GW approximation, where G stands for the oneparticle Green's function and W stand for the screened Coulomb interaction [50]. Although hybrid DFT functionals and the GW approximation produce significantly improved band gaps, their high computational cost limits their applicability to relatively small system sizes.…”

Section: Introductionmentioning

confidence: 99%

“…Although hybrid DFT functionals and the GW approximation produce significantly improved band gaps, their high computational cost limits their applicability to relatively small system sizes. Therefore, these methods have been used only for periodic heterostructures of InAs/GaSb with very few layers [49,50]. DFT studies of large interface slab models with vacuum regions have not been conducted.…”

Section: Introductionmentioning

confidence: 99%

First principles feasibility assessment of a topological insulator at the InAs/GaSb interface

Yang,

Dardzinski,

Hwang

et al. 2021

Preprint

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First principles simulations are conducted to shed light on the question of whether a twodimensional topological insulator (2DTI) phase may be obtained at the interface between InAs and GaSb. To this end, the InAs/GaSb interface is compared and contrasted with the HgTe/CdTe interface. Density functional theory (DFT) simulations of these interfaces are performed using a machine-learned Hubbard U correction [npj Comput. Mater. 6, 180 (2020)]. For the HgTe/CdTe interface our simulations show that band crossing is achieved and an inverted gap is obtained at a critical thickness of 5.1 nm of HgTe, in agreement with experiment and previous DFT calculations. In contrast, for InAs/GaSb the gap narrows with increasing thickness of InAs; however the gap does not close for interfaces with up to 50 layers (about 15 nm) of each material. When an external electric field is applied across the InAs/GaSb interface, the GaSb-derived valence band maximum is shifted up in energy with respect to the InAs-derived conduction band minimum until eventually the bands cross and an inverted gap opens. Our results show that it may be possible to reach the topological regime at the InAs/GaSb interface under the right conditions. However, it may be challenging to realize these conditions experimentally, which explains the difficulty of experimentally demonstrating an inverted gap in InAs/GaSb.

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Many-body perturbation theory study of type-II InAs/GaSb superlattices within the GW approximation

Cited by 10 publications

References 38 publications

Best practices for first-principles simulations of epitaxial inorganic interfaces

Best practices for first-principles simulations of epitaxial inorganic interfaces

Advancing carrier transport models for InAs/GaSb type-II superlattice MWIR photodetectors

First principles feasibility assessment of a topological insulator at the InAs/GaSb interface

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