Purely Spatial Quantum Diffusion of H Atoms in Solid H-2 at Temperatures below 1 K

: Sheludiakov Sergei, Lee D. M., Khmelenko Vladimir V., Järvinen Jarno, Ahokas Janne, Vasiliev Sergey

Publisher: AMER PHYSICAL SOC

: 2021

: Physical Review Letters

: PHYSICAL REVIEW LETTERS

: PHYS REV LETT

: ARTN 195301

: 126

: 19

: 5

: 0031-9007

: 1079-7114

DOI: https://doi.org/10.1103/PhysRevLett.126.195301(external)

: https://research.utu.fi/converis/portal/detail/Publication/59546959(external)

We report on a direct measurement of the quantum diffusion of H atoms in solid molecular hydrogen films at T = 0.7 K. We obtained a rate of pure spatial diffusion of H atoms in the H-2 films, D-d = 5(2) x 10(-17) cm(2) s(-1), which was 2 orders of magnitude faster than that obtained from H atom recombination, the quantity used in all previous work to characterize the mobility of H atoms in solid H-2. We also observed that the H-atom diffusion was significantly enhanced by injection of phonons. Our results provide the first measurement of the pure spatial diffusion rate for H atoms in solid H-2, the only solid state system beside He-3 - He-4 mixtures, where atomic diffusion does not vanish even at temperatures below 1 K.

PhysRevLett.126.195301.pdf