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Low temperature physics, including the physics of highly confined superfluid 3He; disordered superfluids; glass at low temperatures, and incorporation of micro- and nano-mechanical resonators into low temperature apparatus.
- Laboratory of Atomic and Solid State Physics (LASSP)
- Cornell Center for Materials Research (CCMR)
- Kavli Institute at Cornell for NanoScale Science
Significant effort is devoted to the topological superfluid 3He. Under confinement, the role of surfaces, edges and geometry becomes important and represents the opportunity to explore and utilize properties of this most unusual state of matter. We have constructed (and operated) a series of micromachined cells to probe superfluid 3He in the “2D” limit, where the superfluid is confined between two well characterized silicon/glass surfaces separated by distances on the order of a few coherence lengths. New experiments are planned using a thermal conduction cells, cells where there are many interfaces possible between the competing A and B phases, in others where the nucleation of the B phase from the A phase will be examined thoroughly. Cells involving direct wafer bonding will probe the superfluid under more confinement where novel superfluid phases are expected to emerge. A next generation of cells where transport behavior akin to the Quantum Hall effect, to SNS and NSN junctions are also being planned. Devices that are ready for mounting include a state-of-the-art nano string to be operated in 3He to probe the superfluid gap locally as well as explore interactions with quasiparticles. Other topics under active investigation are non-classical flow properties of confined 3He.
The study of superfluid 3He in aerogel: We use high Q oscillators, and thermal conductivity to look for phase transitions and assay the superfluid fraction of 3He in aerogel in the millikelvin temperature range. We are exploring the A-B transition, effects of magnetic field to probe the nature of the superfluid as well as new anisotropic aerogels to “orient” the superfluid order parameter.
Abhilash Sebastian, Nik Zhelev, Anna Eyal
Michael Terilli, Open
The A-B transition in superfluid helium-3 under confinement in a thin slab geometry, N. Zhelev, T.S. Abhilash, E.N. Smith, R.G. Bennett, X. Rojas, L. Levitin, J. Saunders, and J.M. Parpia Nature Communications (2017) DOI: 10.1038/ncomms15963
Low-Power Photothermal Self-Oscillation of Bimetallic Nanowires, Roberto De Alba, T. S. Abhilash, Richard H. Rand, Harold G. Craighead, and Jeevak M. Parpia, Nano Letters DOI: 10.1021/acs.nanolett.6b04769 http://pubs.acs.org/doi/pdfplus/10.1021/acs.nanolett.6b04769
Intertwined superfluid and density wave order in two-dimensional 4He, J. Nyeki, A. Phillis, A. Ho, D. Lee, P. Coleman, J. Parpia, B. Cowan and J. Saunders Nature Physics, 13 455-459 (2017)
Tunable phonon-cavity coupling in graphene membranes, R. De Alba, F. Massel, I. R. Storch, T. S. Abhilash, A. Hui, P. L. McEuen, H. G. Craighead J. M. Parpia Nature Nanotechnology 11, 741–746 (2016). doi:10.1038/nnano.2016.86 http://www.nature.com/nnano/journal/v11/n9/full/nnano.2016.86.html
Phase Diagram of the Topological Superfluid 3He Confined in a Nanoscale Slab Geometry, Levitin, L.V.; Bennett, R.G.; Casey, A.; Cowan, B.; Saunders, J.; Drung, D.; Schurig, T.; Parpia, J.M. Science, 340, 841-4, (2013).
Observation of a new superfluid phase for 3He embedded in nematically ordered aerogel, N. Zhelev, M. Reichl, T.S. Abhilash, E.N. Smith, K.X. Nguyen, E.J. Mueller J.M. Parpia, Nature Communications, (2016) DOI: 10.1038/ncomms12975