TY - JOUR
T1 - Signatures of an annular Fermi sea
AU - Jo, Insun
AU - Liu, Yang
AU - Pfeiffer, L. N.
AU - West, K. W.
AU - Baldwin, K. W.
AU - Shayegan, M.
AU - Winkler, R.
N1 - Publisher Copyright:
© 2017 American Physical Society.
PY - 2017/1/3
Y1 - 2017/1/3
N2 - The concept of a Fermi surface, the constant-energy surface containing all the occupied electron states in momentum, or wave-vector (k), space plays a key role in determining electronic properties of conductors. In two-dimensional (2D) carrier systems, the Fermi surface becomes a contour which, in the simplest case, encircles the occupied states. In this case, the area enclosed by the contour, which we refer to as the Fermi sea (FS), is a simple disk. Here we report the observation of an FS with a new topology, namely, an FS in the shape of an annulus. Such an FS is expected in a variety of 2D systems where the energy band dispersion supports a ring of extrema at finite k, but its experimental observation has been elusive. Our study provides (1) theoretical evidence for the presence of an annular FS in 2D hole systems confined to wide GaAs quantum wells and (2) experimental signatures of the onset of its occupation as an abrupt rise in the sample resistance, accompanied by a sudden appearance of Shubnikov-de Haas oscillations at an unexpectedly high frequency whose value does not simply correspond to the (negligible) density of holes contained within the annular FS.
AB - The concept of a Fermi surface, the constant-energy surface containing all the occupied electron states in momentum, or wave-vector (k), space plays a key role in determining electronic properties of conductors. In two-dimensional (2D) carrier systems, the Fermi surface becomes a contour which, in the simplest case, encircles the occupied states. In this case, the area enclosed by the contour, which we refer to as the Fermi sea (FS), is a simple disk. Here we report the observation of an FS with a new topology, namely, an FS in the shape of an annulus. Such an FS is expected in a variety of 2D systems where the energy band dispersion supports a ring of extrema at finite k, but its experimental observation has been elusive. Our study provides (1) theoretical evidence for the presence of an annular FS in 2D hole systems confined to wide GaAs quantum wells and (2) experimental signatures of the onset of its occupation as an abrupt rise in the sample resistance, accompanied by a sudden appearance of Shubnikov-de Haas oscillations at an unexpectedly high frequency whose value does not simply correspond to the (negligible) density of holes contained within the annular FS.
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U2 - 10.1103/PhysRevB.95.035103
DO - 10.1103/PhysRevB.95.035103
M3 - Article
AN - SCOPUS:85010778023
SN - 2469-9950
VL - 95
JO - Physical Review B
JF - Physical Review B
IS - 3
M1 - 035103
ER -