Dr. Aleksandar Zivkovic

Research Interests

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Dear reader,

Thanks for dropping by. Even if you opened this page accidentally or pressed the wrong button, you might want to stay and have a read - a lot of great discoveries happened by chance anyway!

I mainly work in the field of computational modelling of materials, while relying on colleagues and collaborators to do the experimental counterpart. What do I mainly use? Density functional theory and its extensions (hybrid functionals) as well as molecular dynamics in its ab-initio and machine learned form. What for? To study structural, elastic, electronic, lattice, and optical properties of materials. I try to connect atomic-scale simulations to macroscopic material behaviour. Why? To have better predictive understanding of naturally occurring minerals and their synthetic analogues.

"The principal applications of any sufficiently new and innovative technology always have been – and will continue to be – applications created by that technology" - Kroemer’s Lemma of New Technology

Current research topics include (but not limited to!)

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Earth-abundant materials for solar energy

I study the photovoltaic properties of naturally occurring minerals and geomaterials using first-principles simulations. Geophotovoltaics – a term I'd like to tentatively coin here – is the idea that Earth-abundant geological minerals are intrinsically semiconducting and can perform photon-to-electron conversion. Nature has already prototyped this, rather quietly, through compounds hiding in plain sight.

Take pyrite, for instance: it has a band gap of around 0.95 eV and a favourable optical absorption coefficient with the potential to outperfor silicon by two orders of magnitude. It's also non-toxic, composed of two of the most common elements in the crust, and geologically speaking, dirt cheap. Or consider chalcopyrite, whose crystal structure literally gave its name to an entire family of modern solar cell technologies. The connection between ore mineralogy and solar technology is not metaphorical; it is structural. And then there are the Fe- and Mn-(oxyhydr)oxide mineral coatings on desert and karst rocks, which were recently shown to spontaneously generate measurable photocurrents under sunlight – essentially acting as natural photoelectric generators, covering vast rock surfaces across the planet.

What first-principles simulations bring to this picture is the ability to probe why a given mineral works (or doesn't), to tune band gaps through substitution and doping, and to screen the enormous, untapped diversity of mineral structure types for photovoltaic merit – all before a single crystal is grown in the lab. The approximately 6,000 known mineral species represent a largely unexplored library of semiconductor candidates. We've barely opened the catalogue.

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Cool carbonates

The MgO–CO₂–H₂O system harbours a surprisingly rich zoo of hydrated phases that form at temperatures near the freezing point of water – a regime long relevant to glacial geochemistry, carbon capture, and icy planetary surfaces, yet whose phase diagram still contains significant gaps. Our work targets precisely these gaps.

Recently (see work below), we reported on a new tetrahydrate phase, MgCO₃·4H₂O, that fills the space between the well-known lansfordite (MgCO₃·5H₂O) and nesquehonite (MgCO₃·3H₂O). It forms from the hexahydrate by releasing two weakly bonded water molecules per formula unit – a subtle structural adjustment that preserves the edge-sharing octahedral pairs of the parent structure while the layers quietly relax into a new structure. DFT phonon calculations confirmed the structural stability of the proposed phase (at least at low temperatures), and the simulated diffraction pattern agrees with experiment once crystalline disorder from the transformation process is accounted for.

What makes this particularly interesting is that the phase selection – which hydrate you actually get – depends sensitively on many parameters, not just on equilibrium thermodynamics or temperature. The low-temperature carbonate landscape is shaped as much by the path as by the destination. Further work is envisaged on mapping out the full low-temperature carbonate landscape.

Jordan, G., Strohm, S.B., Živković, A. et al. Filling the gap between lansfordite and nesquehonite: MgCO3·4H2O, a new magnesium carbonate hydrate. Phys Chem Minerals 53, 16 (2026). https://doi.org/10.1007/s00269-026-01349-9

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Magnetic minerals and spin dynamics

If one can decipher and elucidate the complex magnetic properties of iron-bearing minerals – such as pyrrhotites, magnetite, iron oxides, to name a few – then a window into the recorded Earth’s magnetic field becomes clear. The idea is elegant: certain minerals, when they form or cool through specific temperatures, lock in a snapshot of the ambient magnetic field. Billions of such snapshots, preserved in rocks worldwide, constitute the paleomagnetic record. Reading them correctly requires understanding, at the atomic scale, precisely how the magnetic signal got recorded in the first place.

Consider magnetite: is so well-studied it can feel familiar, yet its behaviour at nanometre grain sizes and in mixed assemblages with other phases continues to surprise. By linking atomic-scale spin structure and magnetic anisotropy energy (calculated from DFT with spin-orbit coupling) to macroscopic rock-magnetic observables, this work aims to contribute to interpreting paleomagnetic signals and understanding geomagnetic reversals. This research is developed in collaboration with the group of Prof. Stuart Gilder (LMU Geophysics), coordinator of the DFG Priority Programme DeepDyn: Reconstruction of the Dynamics of Earth's Deep Interior.

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Materials Surface and Interface Chemistry (“Putting things on top of other things”)

As Feynman put it, there is plenty of room at the bottom – and at surfaces and interfaces, that room is where everything happens.

There is hardly any material isolated from its surroundings. Every mineral grain has a surface, every surface meets something else, and those contact regions often decide how a material actually behaves. Understanding atomic-scale processes at mineral surfaces and interfaces – defect formation, charge transfer, adsorption reactions, and the role of interface chemistry in stability and reactivity – is therefore a particular interest of mine. Take an example from my earlier work on the CuO/Cu₂O epitaxial heterostructure, where hybrid DFT calculations showed that the interface can host new electronic states that belong to neither bulk phase alone, arising instead from changes in coordination and charge redistribution across the boundary. In other words, interfaces are not merely where two materials touch; they are places where new behaviour can emerge. Understanding and predicting that behaviour remains a formidable challenge, and precisely the kind that motivates the most.

Publications