Remarks by Sotirios-Ioannis Lekkas

On February 9, 2022, the International Court of Justice (ICJ) rendered its judgment on the reparations phase of the Armed Activities (DRC v. Uganda) case which related to the Democratic Republic of Congo's (DRC) claims against Uganda arising from the Second Congo War.1 The judgment concluded a case which had all the hallmarks of a landmark: an exceptionally large-scale, protracted, and complex armed conflict, a key actor as the respondent, and virtually unfettered material jurisdiction of the Court. As a reminder, in 1999, the Court was seised with DRC's claims against Uganda arising from the (then ongoing) Second Congo War. Similar claims against Rwanda and Burundi failed before reaching the merits stage. In 2005, the Court rendered its judgment on the merits declaring Uganda responsible for violating the principle of non-use of force and non-intervention by the acts of its own forces and by supporting armed groups in the DRC.2 The Court also found Uganda responsible for breaches of international humanitarian law and international human rights law, and for plundering DRC's natural resources.3 The Court concluded that Uganda had to make reparation to the DRC for the injury caused by its internationally wrongful acts and enjoined the parties to enter into negotiations for that purpose.4 After almost ten years of sporadic and fruitless discussions, in 2015, the DRC brought the case back to the Court for conclusive resolution

An analysis of atomic manipulation, intermolecular resolution and the artefacts of dynamic force microscopy

In this thesis we go through a journey of atomic manipulation of Pb dimers on Si(100), then we examine the limitations of AFM in inter- molecular resolution and we take a closer look at a very promising technique named simultaneous STM/AFM which opens new horizons in the field but is part of an ongoing debate as it is still under development. NC-AFM imaging of adsorbed Pb dimers on Si(100) provided detailed information of the Pb configuration, which agrees with previous STM studies. The lateral force required to move a Pb dimer is related to the adsorption of the dimer on the surface, the associated potential energy land scape and in some cases the interaction of the Pb dimer with its neighbouring dimers. In the next part of this thesis, we examine the adsorption of a small organic molecule (NTCDI) on Si(111)-(7×7) and we report two energetically preferable geometries among others. In the last part of this thesis, we present an analysis of the crosstalk effect using an Omicron commercial qPlus sensor and a home built sensor with two system configurations and we compare them with a Createc commercial system. The results show that in order to avoid crosstalk the range of the STM operational pre-amplifier and the optimal elec- tronics wiring play a major role

5 - Uses of the work of International Law Commission on state responsibility in international investment arbitration

The Articles on State Responsibility for Internationally Wrongful Acts (‘ARSIWA’) constitute an experiment in international law-making. Unlike other successful projects of the International Law Commission (‘ILC’), such as its work on the law of treaties and diplomatic and consular relations, the ARSIWA have not yet led to the adoption of a multilateral treaty. Yet, their text is cited commonly as the authoritative statement of the law on state responsibility with investment tribunals being by far their most frequent users. This well-recorded paradox calls for a reflection on the ways in which investment tribunals make use of the ARSIWA. This chapter examines the methods which investment tribunals explicitly or implicitly employ when using the ARSIWA in order to determine the content of rules of general international law on state responsibility. The chapter then proceeds to critically assess these findings from two perspectives: the overarching aims of the law of state responsibility and the doctrine of sources of international law. The chapter synthesises these empirical and doctrinal insights into a proposal for a common framework for the use of ARSIWA

Mechano-chemical manipulation of Sn chains on Si(1 0 0) by NC-AFM

We investigate the atomic structure of Sn dimer chains grown on the Si(1 0 0) surface using non-contact atomic force microscopy (NC-AFM) at cryogenic temperatures. We find that similar to the native Si(1 0 0) dimer structure, the ground state of the Sn dimer structure is buckled at low temperature. At 5 K we show that the buckling state of the Sn dimers may be controllably, and reversibly, manipulated with atomic precision by close approach of the tip, without modification of the underlying substrate buckling structure. At intermediate cryogenic temperatures we observe changes in the configuration of the dimer chains in the region where the tip-sample interaction is very weak, suggesting that the energy barrier to transit between configurations is sufficiently small to be surmounted at 78 K

Nano-contact microscopy of supracrystals

Background: Highly ordered three-dimensional colloidal crystals (supracrystals) comprised of 7.4 nm diameter Au nanocrystals (with a 5% size dispersion) have been imaged and analysed using a combination of scanning tunnelling microscopy and dynamic force microscopy. Results: By exploring the evolution of both the force and tunnel current with respect to tip–sample separation, we arrive at the surprising finding that single nanocrystal resolution is readily obtained in tunnelling microscopy images acquired more than 1 nm into the repulsive (i.e., positive force) regime of the probe–nanocrystal interaction potential. Constant height force microscopy has been used to map tip–sample interactions in this regime, revealing inhomogeneities which arise from the convolution of the tip structure with the ligand distribution at the nanocrystal surface. Conclusion: Our combined STM–AFM measurements show that the contrast mechanism underpinning high resolution imaging of nanoparticle supracrystals involves a form of nanoscale contact imaging, rather than the through-vacuum tunnelling which underpins traditional tunnelling microscopy and spectroscopy

Imaging and manipulation of adsorbed Pb adatom structures on the Si(100) surface by noncontact atomic force microscopy

We performed imaging and manipulation of epitaxially grown Pb adatom structures on the Si(100) surface by noncontact atomic force microscopy (NC-AFM) in ultra-high-vacuum (UHV) and at cryogenic temperatures. We observe several distinct contrast modes during imaging, which we assign to termination of the scanning probe tip by either a single Si, or single Pb, atom, via quantitative comparison of atomic resolution force spectroscopy experiments with ab initio density functional theory (DFT) simulations. We show that the Pb adatom structures can be controllably manipulated via mechanochemical means and identify a novel semideterministic manipulation strategy that arises from the combination of low temperature operation and the asymmetric diffusion barriers present on the Si(100) surface

Role of defects on the electronic and magnetic properties of CrAs/InAs and CrAs/CdSe half-metallic interfaces

We present an extended study of single impurity atoms at the interface between the half-metallic ferromagnetic zinc-blende CrAs compound and the zinc-blende binary InAs and CdSe semiconductors in the form of very thin multilayers. Contrary to the case of impurities in the perfect bulk CrAs studied in [I. Galanakis and S.G. Pouliasis, J. Magn. Magn. Mat. 321 (2009) 1084] defects at the interfaces do not alter in general the half-metallic character of the perfect systems. The only exception are Void impurities at Cr or In(Cd) sites which lead, due to the lower-dimensionality of the interfaces with respect to the bulk CrAs, to a shift of the $p$ bands of the nearest neighboring As(Se) atom to higher energies and thus to the loss of the half-metallicity. But Void impurities are Schottky-type and should exhibit high formation energies and thus we expect the interfaces in the case of thin multilayers to exhibit a robust half-metallic character

Simulated structure and imaging of NTCDI on Si(1 1 1)-7 × 7 : a combined STM, NC-AFM and DFT study

The adsorption of naphthalene tetracarboxylic diimide (NTCDI) on Si(1 1 1)-7 × 7 is investigated through a combination of scanning tunnelling microscopy (STM), noncontact atomic force microscopy (NC-AFM) and density functional theory (DFT) calculations. We show that NTCDI adopts multiple planar adsorption geometries on the Si(1 1 1)-7 × 7 surface which can be imaged with intramolecular bond resolution using NC-AFM. DFT calculations reveal adsorption is dominated by covalent bond formation between the molecular oxygen atoms and the surface silicon adatoms. The chemisorption of the molecule is found to induce subtle distortions to the molecular structure, which are observed in NC-AFM images