Nature of the hole states in Li-doped NiO

Chen, Hungru; Harding, John H.

doi:10.1103/physrevb.85.115127

Cited by 72 publications

(78 citation statements)

References 30 publications

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“…One of these cells contains 16 atoms and the other contains 32 atoms. [59] But they only considered one unit cell structure and therefore did not find any other state devoid of Ni 3 + . This cell was derived from a special quasi-random structure (SQS) unit cell for the bulk at an alloying concentration of x = 0.25 (for more details see the Computational Details Section).…”

Section: Resultsmentioning

confidence: 99%

Significant Reduction in NiO Band Gap Upon Formation of Li_xNi_1−xO alloys: Applications To Solar Energy Conversion

et al. 2013

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Long-term sustainable solar energy conversion relies on identifying economical and versatile semiconductor materials with appropriate band structures for photovoltaic and photocatalytic applications (e.g., band gaps of ∼ 1.5-2.0 eV). Nickel oxide (NiO) is an inexpensive yet highly promising candidate. Its charge-transfer character may lead to longer carrier lifetimes needed for higher efficiencies, and its conduction band edge is suitable for driving hydrogen evolution via water-splitting. However, NiO's large band gap (∼ 4 eV) severely limits its use in practical applications. Our first-principles quantum mechanics calculations show band gaps dramatically decrease to ∼ 2.0 eV when NiO is alloyed with Li2O. We show that Lix Ni1-x O alloys (with x=0.125 and 0.25) are p-type semiconductors, contain states with no impurity levels in the gap and maintain NiO's desirable charge-transfer character. Lastly, we show that the alloys have potential for photoelectrochemical applications, with band edges well-placed for photocatalytic hydrogen production and CO2 reduction, as well as in tandem dye-sensitized solar cells as a photocathode.

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Section: Resultsmentioning

confidence: 99%

Significant Reduction in NiO Band Gap Upon Formation of Li_xNi_1−xO alloys: Applications To Solar Energy Conversion

et al. 2013

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“…[37] For 2D situations, some progresses have been achieved recently. [38] In our future investigations we will go along this direction.…”

Section: Summary and Discussionmentioning

confidence: 97%

Global Quantum Discord in Transverse‐Field Ising Models on N × N Square Lattices

Sun

Zhou

Wang

et al. 2019

Physica Status Solidi (b)

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Global quantum discord (GQD) in two‐dimensional (2D) transverse‐field Ising models on N × N square lattices at zero temperature and finite temperatures are studied. First, the GQD Gtrue(ρ2×2true) defined on the reduced density matrix ρ2×2 of a 2 × 2 sub‐square in the center of the N × N lattices, with N=4, 5, 6, 7, ∞ is studied. It is found that Gtrue(ρ2×2true) shows little size dependence in the strong‐field and weak‐field limit, and presents dramatic size dependence in the middle‐field region. The results are explained by short‐range correlations in non‐critical regions and long‐range correlations in critical regions of the models, respectively. Then the scaling behavior of the GQD Gtrue(true|ψg〉true) of the ground states for the entire N × N squares is studied. It is found that Gtrue(true|ψg〉true) contains a 1D contribution (corresponding to the side length of the squares) and a 2D contribution (corresponding to the area of the squares). Furthermore, the effect of thermodynamic fluctuations on GQD by investigating the thermal‐state GQD Gtrue(e−HkBTtrue) is considered. In high‐temperature regions, GQD is always destroyed by thermodynamic fluctuations for any strength of the magnetic field. However, in low‐temperature regions, some thermal enhancement of GQD under weak fields and some thermal robustness of GQD under strong fields is observed. The results are explained by the low‐lying energy states and the energy gap of the models.

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“…Many different tensor network structures have been developed over the years for solving different problems like the matrix product states (MPS), [68][69][70] projective entangled pair states (PEPS), [14] multiscale entanglement renormalization ansatz (MERA), [16] branching, [71,72] and tree tensor network, [73] matrix product operator, [74][75][76][77] projective entangled pair operator, [78][79][80] and continuous tensor networks. [81][82][83] A large number of numerical algorithms based on tensor networks are now available, including the density-matrix renormalization group, [13] folding algorithm, [15] entanglement renormalization, [16] time-evolving block decimation, [17] and tangent space method.…”

Section: Tensor Networkmentioning

confidence: 99%

Quantum Neural Network States: A Brief Review of Methods and Applications

et al. 2019

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One of the main challenges of quantum many‐body physics is the exponential growth in the dimensionality of the Hilbert space with system size. This growth makes solving the Schrödinger equation of the system extremely difficult. Nonetheless, many physical systems have a simplified internal structure that typically makes the parameters needed to characterize their ground states exponentially smaller. Many numerical methods then become available to capture the physics of the system. Among modern numerical techniques, neural networks, which show great power in approximating functions and extracting features of big data, are now attracting much interest. In this work, the progress in using artificial neural networks to build quantum many‐body states is reviewed. The Boltzmann machine representation is taken as a prototypical example to illustrate various aspects of the neural network states. The classical neural networks are also briefly reviewed, and it is illustrated how to use neural networks to represent quantum states and density operators. Some physical properties of the neural network states are discussed. For applications, the progress in many‐body calculations based on neural network states, the neural network state approach to tomography, and the classical simulation of quantum computing based on Boltzmann machine states are briefly reviewed.

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Nature of the hole states in Li-doped NiO

Cited by 72 publications

References 30 publications

Significant Reduction in NiO Band Gap Upon Formation of Li_xNi_1−xO alloys: Applications To Solar Energy Conversion

Significant Reduction in NiO Band Gap Upon Formation of Li_xNi_1−xO alloys: Applications To Solar Energy Conversion

Global Quantum Discord in Transverse‐Field Ising Models on N × N Square Lattices

Quantum Neural Network States: A Brief Review of Methods and Applications

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Nature of the hole states in Li-doped NiO

Cited by 72 publications

References 30 publications

Significant Reduction in NiO Band Gap Upon Formation of LixNi1−xO alloys: Applications To Solar Energy Conversion

Significant Reduction in NiO Band Gap Upon Formation of LixNi1−xO alloys: Applications To Solar Energy Conversion

Global Quantum Discord in Transverse‐Field Ising Models on N × N Square Lattices

Quantum Neural Network States: A Brief Review of Methods and Applications

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Significant Reduction in NiO Band Gap Upon Formation of Li_xNi_1−xO alloys: Applications To Solar Energy Conversion

Significant Reduction in NiO Band Gap Upon Formation of Li_xNi_1−xO alloys: Applications To Solar Energy Conversion