Anharmonic multi-phonon nonradiative transition: An ab initio calculation approach

Xiao, Yao; Wang, Zi-Wu; Shi, Lin; Jiang, Xiangwei; Li, Shu-Shen; Wang, LinWang

doi:10.1007/s11433-020-1550-4

Cited by 34 publications

(19 citation statements)

References 35 publications

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“…First-principles calculations have obtained great success in the research of GaN-based semiconductors 24,28,29,38,39 . In this work, we theoretically demonstrated by first-principles calculations that in GaN-based semiconductors, the 4 | 8 configuration is more energetically favorable than the wurtzite configuration after reducing the dimensions from bulk to 2D structures.…”

Section: Introductionmentioning

confidence: 99%

Elimination of the internal electrostatic field in two-dimensional GaN-based semiconductors

et al. 2020

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GaN-based semiconductors are promising materials for solid-state optoelectronic applications. However, the strong internal electrostatic field (IEF) along the [0001] direction is a serious problem that harms the efficiency of lighting devices based on GaNbased semiconductors due to the quantum confined Stark effect. Here we theoretically predict a method, reducing the dimensions from bulk to two-dimensional (2D) structures, to fundamentally remove the IEF. After thinning the materials to several nanometers, the wurtzite configuration (with strong IEF) spontaneously transform to the haeckelite (4 | 8) configuration (without IEF) due to the more stable neutral surface in the 4 | 8 configuration. Meanwhile, the 4 | 8 configuration maintain optoelectronic properties comparable to or even better than those of the wurtzite configuration. By carefully analyzing the interaction between 2D GaN and different types of substrates (SiC and graphene), we not only provide clear physical insights for experimental results but also address a "thickness-controlled" vdW epitaxy scheme to experimentally realize the 4 | 8 configuration. We believe that the 4 | 8 configuration without IEF is a prospective material for diverse optoelectronic applications. In addition, we propose a point of view in engineering the properties of GaN-based semiconductors.

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Section: Introductionmentioning

confidence: 99%

Elimination of the internal electrostatic field in two-dimensional GaN-based semiconductors

et al. 2020

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“…It is ascribed to the essence that the distortion of the Pb-Br bond is harder than that of the Pb-I bond determined by the bond length, which is reflected by the coupling parameter α as listed in Table I. We have noticed that the effective phonon modes and relaxation energy could be obtained from the first-principles calculations [39][40][41], gaining the more accurate evaluations for HR factors. Our results will also provide an important theoretical reference for these calculations.…”

Section: Resultsmentioning

confidence: 99%

Infrared optical absorption of Frohlich polaron in metal halide perovskites

Chen¹,

Liu²,

Ma³

et al. 2022

Preprint

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The formation of Fröhlich polaron in metal halide perovskites, arising from the charge carrierlongitudinal optical (LO) phonon coupling, has been proposed to explain their exceptional properties, but the effective identification of polaron in these materials is still a challenge task. Herein, we theoretically present the infrared optical absorption of Fröhlich polaron based on Huang-Rhys model. We find that multiphonon overtones are appeared as the energy of incident photon matches the multiple LO phonons, wherein the average phonon numbers of a polaron can be directly evaluated by the order of the strongest overtone. These multiphonon structures sensitively depend on the scale of electronic distribution in the ground state and the dimensionality of the perovskite materials, which gives the enlightenment for the effective modulation of competing processes between the polaron formation and carrier cooling. Moreover, the order of the strongest overtone shifts to the higher ones with temperature, providing a potential proof of the carriers mobility affected by LO phonons scattering. The present model not only suggests a direct way to verify Fröhlich polaron, but also enriches the understanding of the polaron properties in metal halide perovskites.

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“…[51] It should be noted that our electron-phonon calculations are considered within the harmonic approximation, anharmonic multiphonon process is beyond of the scope. [52] The total current for one spin channel can be expressed the as sum of two terms el in…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…[ 51 ] It should be noted that our electron–phonon calculations are considered within the harmonic approximation, anharmonic multiphonon process is beyond of the scope. [ 52 ] The total current for one spin channel can be expressed the as sum of two terms

I^{σ} = I_{el}^{σ} + I_{in}^{σ}

(σ = up, down) and the spin‐resolved pure elastic current can be described by the Landauer formula

I_{el}^{σ} = \frac{G_{0}}{2 e} \int d ε [n_{normalf} (ε - μ_{normalL}) - n_{normalf} (ε - μ_{normalR})] T^{σ} (ε)

where n f (ε) denotes to the Fermi–Dirac distribution function and μ L/R represents the chemical potential of the left/right electrode. The transmission coefficient can be given by T σ (ε) = Tr[ G r Γ L G a Γ R ] σ , here G r/a is the unperturbed retarded/advanced green function, Γ L/R is the broadening function of the left/right.…”

Section: Theoretical Methodsmentioning

confidence: 99%

Switchable Spin Filters in Magnetic Molecular Junctions Based on Quantum Interference

Huang

Chen

Zeng

et al. 2020

Adv Elect Materials

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The ability to control the degree of spin in molecular junctions (MJs) is attractive for their applications in spintronics. Here, it is demonstrated that spin‐resolved quantum interference (SQI) can effectively improve spin‐filtering behavior of MJs. By first‐principle calculations in combination with nonequilibrium Green's function investigations, spin‐resolved charge transport in graphene/Cr‐porphyrin/graphene MJs shows that, due to the SQI, the tunable spin filtering behaviors can be achieved by changing the length of molecule. The SQI related phase coherence/decoherence in these MJs is revealed by considering the effects of temperature and electron–phonon interactions. Furthermore, a higher spin filtering efficiency in low bias region can be obtained by Cr‐doped in single‐porphyrin junction, due to the Cr‐enhanced SQI. These results show great potential for the application of MJs with SQI in the molecular intergrated circuit and provide a promising way for designing spin molecular devices by using quantum interference.

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Anharmonic multi-phonon nonradiative transition: An ab initio calculation approach

Cited by 34 publications

References 35 publications

Elimination of the internal electrostatic field in two-dimensional GaN-based semiconductors

Elimination of the internal electrostatic field in two-dimensional GaN-based semiconductors

Infrared optical absorption of Frohlich polaron in metal halide perovskites

Switchable Spin Filters in Magnetic Molecular Junctions Based on Quantum Interference

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Anharmonic multi-phonon nonradiative transition: An ab initio calculation approach

Cited by 34 publications

References 35 publications

Elimination of the internal electrostatic field in two-dimensional GaN-based semiconductors

Elimination of the internal electrostatic field in two-dimensional GaN-based semiconductors

Infrared optical absorption of Frohlich polaron in metal halide perovskites

Switchable Spin Filters in Magnetic Molecular Junctions Based on Quantum Interference

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Product

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Infrared optical absorption of Frohlich polaron in metal halide perovskites