Defect-induced supersolidity with soft-core bosons.
More than 40 years ago, Andreev, Lifshitz and Chester suggested the possible existence of a peculiar solid phase of matter, the microscopic constituents of which can flow superfluidly without resistance due to the formation of zero-point defects in the ground state of self-assembled crystals. Yet, a physical system where this mechanism is unambiguously established remains to be found, both experimentally and theoretically. Here we investigate the zero-temperature phase diagram of two-dimensional bosons with finite-range soft-core interactions. For low particle densities, the system is shown to feature a solid phase in which zero-point vacancies emerge spontaneously and give rise to superfluid flow of particles through the crystal. This provides the first example of defect-induced, continuous-space supersolidity consistent with the Andreev-Lifshitz-Chester scenario.
1] Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany [2] National Institute for Theoretical Physics (NITheP), Stellenbosch 7600, South Africa.
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Cinti
Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany.
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Macrì
IQOQI, Austrian Academy of Science, and Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria.
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Lechner
IPCMS (UMR 7504) and ISIS (UMR 7006), Université de Strasbourg and CNRS, 67000 Strasbourg, France.
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Pupillo
Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany.
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Pohl