Soliton formation in an exciton-polariton condensate at a bound state in the continuum

Bound states in the continuum (BIC) are of special interest in photonics due to their theoretically infinite radiative lifetime. Here, we design a structure composed of a GaN layer with guided exciton-polaritons and a TiO$_2$ 1D photonic crystal slab. The photonic BIC hosted by the photonic crystal slab couples with the excitons of GaN to form a polaritonic BIC with a negative mass. This allows condensation to be reached with a low threshold in a structure suitable for electrical injection, paving the way for room-temperature polariton microdevices. We study in detail how the repulsive interaction between exciton-polaritons affects the condensate distribution in reciprocal space and, consequently, the condensate's overlap with the BIC resonance and, therefore, the condensate lifetime. We study an intrinsic contribution related to the formation of a bright soliton and the extrinsic contribution related to the interaction with an excitonic reservoir induced by spatially focused non-resonant pumping. We then study the peculiar dynamics of the condensation process in a BIC state for interacting particles using Boltzmann equations and hybrid Boltzmann-Gross Pitaevskii equations. We find optimal conditions allowing one to benefit from the long lifetime of the BIC for polariton condensation in a real structure

Sustainable finance and the role of corporate governance in preventing economic crimes

Despite the growing popularity of sustainable finance and the emergence of an industry dedicated to solving urgent global problems while making profits, highprofile corporate governance failures do not appear to slow down. In 2018, Abraaj, a well-known figure in impact investing, collapsed after its CEO was arrested for fraud and misappropriation of funds. Similarly, in 2020, Boohoo, a previously reputable online fashion retailer, faced intense scrutiny over work slavery that ended up being the subject of a UK parliament inquiry and lost support from responsible investors. This chapter proposes to go back to these two recent high-profile cases to discuss the extent to which the lack of accountability, ethics, and corporate governance might be conducive to economic crimes and detrimental to investors willing to embrace the principles of sustainable finance. Then, the concept of sustainable corporate governance is introduced, and a discussion of its implications for the fields of corporate governance and criminology is provided. Finally, two incentive alignment mechanisms promoting sustainable corporate governance, CSR committees and CSR contracting, are presented to help align executives’ interests with those of all legitimate stakeholders. This chapter contributes to the literature on corporate governance and criminology by examining the role of a more sustainable governance in preventing and deterring economic crimes

CEO-to-Worker pay ratio, say on pay votes, and executive compensation

This study investigates the extent to which the CEO-to-Worker pay ratio affects shareholders’ say on pay votes and consequently examine whether shareholder opposition to pay gaps influence future CEO compensation. The effects of the implementation of the CEO-to-Worker pay ratio disclosure rule (2017) and the Portland Surplus tax (2018) are also discussed. We employ a large and up-to-date sample of US Russell 3,000 companies with 13,885 firm-year observations from 2011 to 2018. We develop and employ a unique measure of the CEO-to-Worker pay ratio allowing us to study time-periods for which data is not available. Using different quantitative estimation methods, we found that the CEO-to-Worker pay ratio is significantly and positively associated with shareholder dissent votes and that a pay gap opposition from shareholders is negatively and significantly associated with future CEO compensation. In addition, mandatory disclosure of the CEO-to-Worker pay ratio has increased the number of shareholder dissent votes the year after its implementation in 2017. By contrast, companies identified by the Portland Surplus tax have not shown higher shareholder dissent votes nor lower future CEO compensation compared to the Russell 3,000 companies. This study has important implications for the corporate governance literature, corporate directors, and policymakers

The effect of CEO‐to‐worker pay disparities on CEO compensation: the mediating role of shareholder say on pay votes

In response to large pay disparities caused by rising CEO compensation and stagnant employee pay, US financial regulators have taken several initiatives to mobilise shareholders. However, the ability of these initiatives to enhance shareholder engagement and reduce excessive CEO compensation has been questioned. Using a large sample of 1594 non-financial firms from the Russell 3000 index over 2013–2019, we disentangle the complex role that shareholder engagement towards CEO-to-worker pay disparities plays on CEO compensation. We find that higher CEO-to-worker pay disparities increase shareholder dissent say on pay votes and that, paradoxically, shareholder dissent say on pay votes increase CEO compensation. Furthermore, we provide evidence that shareholder engagement mediates the relationship between CEO-to-worker pay disparities and CEO compensation through their say on pay votes. Our findings are consistent with the relative deprivation theory as shareholders react to large pay disparities to avoid the negative consequences of a feeling of deprivation on employees. They are also in line with the agency theory, as shareholder reactions to large CEO-to-worker pay disparities trigger reactions from the remuneration committee to better align CEO pay with their interests. Overall, our findings support the existence of a shareholder engagement channel driven by social comparison mechanisms and agency responses. This study has important implications for regulators by unpacking the usefulness of these regulatory initiatives to shareholders and also documenting their unintended consequences on CEO compensation

The effectiveness of CSR committees’ characteristics and CSR contracting

We rely on the stakeholder-agency theory to examine whether the effectiveness of CSR committees influences the initiative of CSR contracting, which consists of tying ESG performance measures to executive compensation contracts. Using a sample of 1,641 observations from 575 U.S. companies over 2015 to 2019, we measure the effectiveness of CSR committees in function of their structural characteristics. We find that an effective independence of CSR committees, proxied by a larger proportion of independent directors and an independent chairperson enhances the likelihood of CSR contracting. Furthermore, we report that an effective structure for CSR committees, captured through a composite score including size, directors’ independence, chairperson’s independence, and meeting frequency, is positively associated with CSR contracting. Overall, our results show that an effective CSR committee improves the controllability of CSR contracting through better monitoring and consideration of all stakeholders’ interests. This study has important implications for practitioners to build more effective CSR committees based on their structural characteristics and for regulators to provide better guidance on their structures and practices

CSR contracting, materiality, and their effects on financial and non-financial performance

Although the recent corporate governance initiative of tying environmental, social, and governance (ESG) targets to executive compensation is gaining popularity in developed economies, difficulties have been reported in their identification and selection due to a heterogeneity of stakeholder interests. Drawing on the agency and stakeholder theories, we apply the concept of materiality for the design of ESG targets in executive compensation and tests its effects on corporate financial and non-financial performance. By focusing on a unique sample of S&P 1,500 companies from 2011 to 2019, we find that material CSR contracting has a negative effect on market-based financial performance and a positive one on environmental performance. These results are robust to endogeneity and further tests suggest that this approach provide greater effects than simply adding general ESG targets in executive compensation. These findings imply a trade-off between corporate financial performance and corporate non-financial performance in the short-term which raises questions about the primary motivations of corporations and the soundness of shareholder-oriented materiality frameworks

Cyclometalated platinum(II) complexes of pyrazole-based, N=C=N-coordinating, terdentate ligands: the contrasting influence of pyrazolyl and pyridyl rings on luminescence.

1,3-Bis(1-pyrazolyl)-5-methyl-benzene, HL(2), undergoes cyclometalation at the C(2) position upon reaction with K(2)PtCl(4), to generate an N=C=N-coordinated complex, PtL(2)Cl. This compound is luminescent in degassed solution at 298 K, emitting in the blue region of the spectrum on the microsecond time scale (lambda(max) = 453 nm, tau = 4.0 micros, Phi(lum) = 0.02, in CH(2)Cl(2)). Compared to the analogous complex Pt(dpyb)Cl that incorporates pyridyl rather than pyrazole rings {dpybH = 1,3-di(2-pyridyl)-benzene}, the excited state is displaced to higher energy by 1700 cm(-1). This effect is rationalized in terms of the poorer pi-acceptor nature of pyrazolyl compared to pyridyl rings, leading to destabilization of the lowest unoccupied molecular orbital, which is largely localized on the heteroaromatic rings in both cases. Cyclic voltammetry and density functional theory calculations reinforce this interpretation, and suggest that the lowest-energy excited state is probably best described as heavily mixed pi(L)/d(Pt)/p(Cl) --> pi*(L) (IL/MLCT/LLCT) in character. 5-Aryl-substituted analogues of HL(2) are accessible in three steps from 1,3,5-tribromobenzene by Pd-catalyzed cross-coupling with aryl boronic acids, followed by copper-catalyzed bromo-iodo exchange, and subsequent amination with pyrazole under relatively mild conditions also catalyzed by copper. The corresponding Pt(II) complexes display red-shifted and more intense luminescence compared to PtL(2)Cl. Ligands incorporating one pyrazole and one pyridyl ring are also accessible; for example, 1-(1-pyrazolyl)-3-(2-pyridyl)benzene, HL(6). Their complexes are highly luminescent in solution; for example, for PtL(6)Cl, lambda(max) = 487 nm, tau = 6.9 micros, Phi(lum) = 0.55, in dilute solution in CH(2)Cl(2). At elevated concentrations, PtL(6)Cl displays an additional excimeric emission band that is substantially blue-shifted compared to that displayed by Pt(dpyb)Cl (bands centered at 645 and 695 nm, respectively), indicating that the presence of the pyrazole ring destabilizes the excimer. The introduction of a methyl substituent into the central aryl ring of such complexes is sufficient to eliminate the excimer emission

A new versatile synthesis of macrotricyclic tetraazacycloalkane-based ligands from bis-aminal derivatives

cited By 30International audienceA new powerful synthesis of symmetrical (two-step) or dissymmetrical (three-step) macrotricyclic cyclen- or cyclam-based ligands is reported. In this procedure, the starting materials are bis-aminals derived from condensation of cyclen or cyclam with glyoxal. The two macrocyclic subunits are linked by two aromatic spacers through nitrogen atoms. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003