Observation of a new superfluid phase for3He embedded in nematically ordered aerogel.
In bulk superfluid3He at zero magnetic field, two phases emerge with the B-phase stable everywhere except at high pressures and temperatures, where the A-phase is favoured. Aerogels with nanostructure smaller than the superfluid coherence length are the only means to introduce disorder into the superfluid. Here we use a torsion pendulum to study3He confined in an extremely anisotropic, nematically ordered aerogel consisting of ∼10 nm-thick alumina strands, spaced by ∼100 nm, and aligned parallel to the pendulum axis. Kinks in the development of the superfluid fraction (at various pressures) as the temperature is varied correspond to phase transitions. Two such transitions are seen in the superfluid state, and we identify the superfluid phase closest to Tcat low pressure as the polar state, a phase that is not seen in bulk3He.
Department of Physics and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
N
N
Zhelev
Department of Physics and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
M
M
Reichl
Department of Physics and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
T S
TS
Abhilash
Department of Physics and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
E N
EN
Smith
School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
K X
KX
Nguyen
Department of Physics and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
E J
http://orcid.org/0000-0001-5186-5889
EJ
Mueller
Department of Physics and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
J M
JM
Parpia
Phys Rev Lett. 2015 Oct 16;115(16):165304
26550884
Phys Rev Lett. 1995 Jun 5;74(23):4667-4670
10058568
Phys Rev Lett. 2007 Jan 26;98(4):045301
17358783
Phys Rev Lett. 2011 Dec 2;107(23):235504
22182100
Phys Rev Lett. 1995 Jul 24;75(4):661-664
10060082
Phys Rev Lett. 2008 May 30;100(21):215304
18518618
Phys Rev Lett. 1995 Nov 20;75(21):3938-3941
10059769
Science. 2014 Apr 18;344(6181):283-5
24744371