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Diamond Ice: How Defects Crystallize Without Nitrogen ✛ ✎ ✦

Original: "A Ginzburg-Landau theory of intrinsic dislocation-loop formation in diamond with machine-learned atomistic simulations"
· Xiaoya Chang, Arsalan Hashemi, Nima Ghafari Cherati, Mikko Karttunen, Adam Gali, Tapio Ala-Nissila
arXiv:2606.29055 · 2026-06-27 · arXiv non-exclusive · independent analysis · 1 min
Materials Computational Physics
Large defects in diamond form abruptly, like ice from water, and no nitrogen is needed, just bond rearrangement.

Using machine learning, a method where a computer learns from precise quantum calculations, scientists tracked thousands of carbon atoms in diamond. It turned out that when individual atoms shift, they don't slowly assemble into defects. The process happens abruptly, like water freezing at zero, and physicists call this a phase transition. Lev Landau developed a theory that describes such jumps, accounting for entropy — the system's tendency toward disorder.

But the big surprise: 98% of the transition energy went into rearranging chemical bonds, not at all into relieving internal stresses. Moreover,

it turned out that nitrogen atoms aren't needed for defect formation, as previously thought — carbon manages on its own.

One type of defect even resembled structures found in silicon.

Understanding this sudden 'crystallization' of defects matters not just for geologists. Diamond is already used in quantum computers and ultrasensitive quantum sensors. And some of the discovered defects create conditions promising for transmitting quantum information.

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A tiny atomic loop-trap harbors energy comparable to hundreds of electron volts, yet doesn't break down, like frozen tension.

F(\psi) = \frac{a}{2} \psi^2 + \frac{b}{4} \psi^4 + \frac{c}{6} \psi^6 - f_{\text{ext}} \psi
a, b, c are constants, ψ is the loop area, and the term f_ext ψ describes the contribution of elastic energy, which turned out to be negligibly small.
\Delta F^* = k_B T \ln(\tau / \tau_0)
This allowed estimating the nucleation energy barrier from the characteristic transition time: τ is the observed time, τ₀ is the atomic attempt time.
Scientists
Emmy NoetherWolfgang PauliEnrico FermiPaul DiracErwin SchrödingerPeter Higgs
Concepts
dislocation first law of thermodynamics energy dissipation radioactive decay first order phase transition nucleation Phase transition diamond nv center time crystal diamond quantum memory discrete time crystal quantum operation crystallization demagnetization star formation solidification false vacuum decay damping bubble nucleation material phase transformation