Optical Absorption by Indirect Excitons in a Transition Metal Dichalcogenide Double Layer

We calculate the binding energy, transition energies, oscillator strength, and absorption coefficient of indirect excitons in transition metal dichalcogenide (TMDC) double layers separated by an integer number of hexagonal boron nitride (h-BN) monolayers. The absorption factor, a dimensionless quantity which gives the fraction of incoming photons absorbed by the indirect excitons in the double layer, is evaluated. The aforementioned optical quantities are obtained for transitions from the ground state to the first two excited states. All quantities are studied as a function of the interlayer separation, which may be experimentally controlled by varying the number of h-BN monolayers between the TMDC layers. Calculations are performed by using the exciton wave function and eigenenergies obtained for the Keldysh potential. For each material, we choose a combination of the exciton reduced mass and the dielectric screening length from the existing literature which give the largest and the smallest indirect exciton binding energy. These combinations of material parameters provide upper and lower bounds on all quantities presented. Our findings can be examined experimentally via two-photon spectroscopy.Comment: 13 pages, 3 figure

Appendix A. Derivation of info-gap robustness formulae for the ecosystem services case study.

Derivation of info-gap robustness formulae for the ecosystem services case study

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Appendix B. Bacterial growth problem demonstrating the potential importance of asymmetric uncertainty in info-gap models.

Bacterial growth problem demonstrating the potential importance of asymmetric uncertainty in info-gap models

Improving the Design of a Conservation Reserve for a Critically Endangered Species

<div><p>Setting aside protected areas is a key strategy for tackling biodiversity loss. Reserve effectiveness depends on the extent to which protected areas capture both <i>known</i> occurrences and areas <i>likely</i> to support the species. We assessed the effectiveness of the existing reserve network for Leadbeater’s Possum (<i>Gymnobelideus leadbeateri</i>) and other forest-dependent species, and compared the existing reserve system to a set of plausible reserve expansion options based on area targets implied in a recent Population Viability Analysis (PVA). The existing Leadbeater’s Reserve and surrounding reserve system captured 7.6% and 29.6% of cumulative habitat suitability, respectively, across the landscape. Expanded reserve scenarios captured 34% to 62% of cumulative habitat suitability. We found acute trade-offs between conserving Leadbeater’s Possum habitat and conserving habitat of other forest-dependent species. Our analysis provides a template for systematically expanding and evaluating reserve expansion options in terms of trade-offs between priority species’ needs.</p></div

Relative probability of occurrence of Leadbeater’s Possum, Greater Glider, Yellow-Bellied Glider and Sooty Owl in the Central Highlands of Victoria, ranked as values (0–1).

<p>Relative probability of occurrence of Leadbeater’s Possum, Greater Glider, Yellow-Bellied Glider and Sooty Owl in the Central Highlands of Victoria, ranked as values (0–1).</p

Improving the Design of a Conservation Reserve for a Critically Endangered Species - Fig 3

<p>Three Zonation solutions modelling the expansion of the reserve system for Leadbeater’s Possum generated using: (a) equal, (b) linear and (c) log species weighting schemes based on threat status and the Maxent SDMs for each species. The equal weighted scenario resulted in the largest reserve expansion in area under scenario 1 and the linear scenario resulted in the largest area for reserve expansion in area under Scenario 2 (see text).</p

The existing conservation reserve network and the Leadbeater’s Possum Reserve in the study area (Source: [30,37]).

<p>The existing conservation reserve network and the Leadbeater’s Possum Reserve in the study area (Source: [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169629#pone.0169629.ref030" target="_blank">30</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169629#pone.0169629.ref037" target="_blank">37</a>]).</p

Pairwise difference (%) of cumulative values of distributions captured under the reserve scenarios using the different species weighting schemes for each of the target species.

<p>Pairwise difference (%) of cumulative values of distributions captured under the reserve scenarios using the different species weighting schemes for each of the target species.</p

Appendix A. SURVIV code for estimating the binomial mixture parameters p and P by maximum likelihood.

SURVIV code for estimating the binomial mixture parameters p and P by maximum likelihood