News

09/2026: A new high-pressure ice phase
The polymorphism of ice is well documented, with over 20 crystalline phases now identified. This huge variety is due to the flexibility of water’s hydrogen bond network. Under pressure, these hydrogen bonds symmetrise, where individual water molecules join to form a single atomic network. The resulting structure, ice X, was the final known ice phase at high pressure – until now. In collaboration with the Howie and Peña-Alvarez groups, we have confirmed the emergence of the first post-symmetrisation ice phase, labeled ice XXII, now published in Nat. Mater.

09/2026: Student presentation prizes
Izzy won the prize for ‘Best Contributed Talk’ at the MLIP School and Workshop at the University of Warwick. In the same week, David won the prize for ‘Best Poster’ at the Annual General Meeting of CCP5, held at the University of Edinburgh. Very well done, Izzy and David!

08/2026: Manganese superhydride
Metal polyhydrides remain an intriguing class of materials, with unusual compositions and structures stabilised at high pressures. Intriguingly, only a single “superhydride” (defined, somewhat arbitrarily, as hydrogen:metal ratio of five or higher) is known for the entire transition metal block (FeH₅). Here, in work led by Dr Kuzovnikov, we have explored the manganese-hydrogen phase diagram, and discovered several new hydrides, including the superhydride MnH₇. In an interesting twist, the structure of MnH₇ is stabilised by nuclear quantum effects. See our paper in Angew. Chem. Int. Ed. for all the details.

07/2026: Ternary H-C-N compounds
The light elements C-N-O, together with lots of hydrogen, are expected to dominate the interiors of outer icy planets. A lot of computational work has been done on various elemental combinations to explore the high-pressure trends within this chemical space. Interestingly, there has been no published work on ternary hydrogen-carbon-nitrogen compounds, which we address here, in collaboration with the groups of Dr Cheng Lu and Dr Bole Chen. The results are now published in Phys. Rev. B.

05/2026: Doped covalent ternary superconductors
We consider carbon clathrate networks, doped with both boron and nitrogen. This leads to compounds that are structurally very stable (in fact, superhard) yet electronically interesting, with reasonable superconducting properties at ambient pressures. A sizeable challenge will remain in the synthesis of these compounds, which are energetically metastable. Our computational survey of these compounds is now published in Acta Mater.

05/2026: Ternary metal-boron hydride
Ternary metal hydrides have emerged as promising candidates to deliver hydride superconductivity at lower pressures. Amongst these, the cubic Mg₂IrH₆ structure type has proven especially interesting. In a high-throughput screening study, we identified a series of boron-based hydrides of this structure that are dynamically stable and superconducting, rivalling the properties of the parent Mg₂IrH₆ compound. The work, led by Dr Feng Peng’s group, is now published in Phys. Rev. B.

04/2026: Special Issue in Mol. Phys.
My PhD supervisor, Prof Peter Schwerdtfeger, celebrated his 70th birthday last year. I was honoured to act as editor of a special issue of the journal Molecular Physics, which celebrates Peter’s wide ranging interests by soliciting original submissions from some of his many collaborators. Have a look at the special issue here to get an idea of the breadth and impact of Peter’s research over the years.

04/2026: Boron-carbon clathrates
Materials with strong covalent bonds can prevail as metastable reaction products with long lifetimes. Carbon structures are a prime example. In addition, metal-doped carbon clathrates have been shown to be interesting superconductors. Here, we probe systematic carbon-boron substitutions in these clathrates to investigate the effect on mechanical and electronic properties. This paper is now out in J. Mater. Chem. C.

03/2026: Superconducting boron carbides
Boron carbide, BC, is a strong material with appreciable polymorphism, driven by both carbon’s affinity to tetrahedral coordination, and boron’s electron efficiency and tendency for multi-centre bonding. Here, in work led by Dr Cheng Lu’s group, we used structure prediction to unearth new BC polymorphs that have interesting electronic properties. The paper is now published in J. Phys.: Cond. Mat.

02/2026: Jinni joins the group
Jinni Yang from Sichuan University will spend a year visiting the group. Her stay is funded by the China Scholarship Council. Jinni is interested in two-dimensional materials, especially those with promising superconducting properties. Welcome to the group, Jinni!

10/2025: Close-packed bromine
The halogen elements (group 17) form molecular crystals, but at high pressure the molecules disintegrate. In this atomic regime, halogens are thought to undergo a series of phase transitions, ultimately reaching a close-packed cubic structure. For bromine, we have now studied this phase sequence, which features three kinds of phase transition: from molecular to atomic structure, via an incommensurately modulated intermediate; from orthorhombic to tetragonal, via second order transition regulated by strong lattice anharmonicity; and from tetragonal to cubic close packed, via conventional first order transition. Painstaking calculations by Dominik Kurzydłowski and experiments by Eric Edmund were key to our understanding; results are now published in Phys. Rev. B.

09/2025: Thermodynamics of dense ices
Ice VII is a central phase in water’s phase diagram, characterised by two intercalating disordered body-centered hydrogen bond networks. Upon cooling, ice VII’s water molecules order into ice VIII; upon compression, the hydrogen bond symmetrise into ice X. Led by Graeme Ackland, we have developed a three-state free energy model that describes the physics of the ice VII-VIII-X phase relations, and reproduces the known phase boundaries. The model predicts that the VII-X transition is a supercritical crossover, with a VII-X critical point potentially hidden within the stability region of ice VIII. This work has just been published in Phys. Rev. B.