APS March Meeting 2016
Volume 61, Number 2
Monday–Friday, March 14–18, 2016;
Baltimore, Maryland
Session E28: Topological Superconductivity
8:00 AM–11:00 AM,
Tuesday, March 15, 2016
Room: 327
Sponsoring
Unit:
DMP
Chair: Abhay Pasupathy, Columbia University
Abstract ID: BAPS.2016.MAR.E28.1
Abstract: E28.00001 : Emergent surface superconductivity in a 3D topological insulator.*
8:00 AM–8:36 AM
Preview Abstract
Abstract
Author:
Lia Krusin-Elbaum
(Department of Physics, The City College of New York – CUNY)
Surfaces of three-dimensional topological insulators have emerged as one of
the most remarkable states of condensed quantum matter where exotic charge
and spin phases of Dirac particles could form. This work reports on novel
mesoscopic superconductivity in the topological insulator Sb$_{2}$Te$_{3}$
with transition to zero resistance induced through a minor tuning of growth
chemistry that depletes bulk conduction channels [1]. The depletion shifts
Fermi energy towards the Dirac point as witnessed by a factor of 300
reduction of bulk carrier density and by the largest carrier mobility
(\textgreater 25, 000 cm$^{2}$V$^{-1}$s$^{-1})$ found in any topological
material of this class. Direct evidence from transport, the unprecedentedly
large diamagnetic screening, and the presence of $\sim $ 25 meV gaps
detected by scanning tunneling spectroscopy reveal the superconducting
condensate to emerge first in surface puddles at unexpectedly high
temperature of $\sim $ 50 K, with the onset of global phase coherence at
$\sim $ 9 K. The unconventional spin response of Sb$_{2}$Te$_{3\, }$[2] and
the presence of subsurface 2DEG quantum well states arising from charge
transfer to the surface [3] are likely to play a role in the emergent
superconducting state. The rich structure of this state lends itself to
manipulation via growth conditions and the material parameters such as Fermi
velocity and mean free path.
[1] Emergent surface superconductivity in the topological insulator
Sb$_{2}$Te$_{3}$, L. Zhao, H. Deng, I. Korzhovska, J. Secor, M.
Begliarbekov, Z. Chen, E. Andrade, E. Rosenthal, A. Pasupathy, V. Oganesyan,
and Lia Krusin-Elbaum, \textit{Nature Comm.} \textbf{6}, 8279 (2015); DOI:10.1038/ncomms9279.
[2] Singular robust room-temperature spin response from topological Dirac
fermions, L. Zhao, H. Deng, I. Korzhovska, Z. Chen, M. Konczykowski, A.
Hruban, V. Oganesyan and Lia Krusin-Elbaum, \textit{Nature Mat.} \textbf{13}, 580 (2014); DOI:
10.1038/nmat3962.
[3] Robust topological interfaces and charge transfer in epitaxial
Bi$_{2}$Se$_{3}$/II-VI semiconductor superlattices, Z. Chen, L. Zhao, K.
Park, T. A. Garcia, M. C. Tamargo, and Lia Krusin-Elbaum, \textit{Nano Lett}. \textbf{15}
(10), 6289 (2015); DOI:10.1021/acs.nanolett.5b01358.
*This work was supported by NSF DMR-1122594, DMR-1420634, DMR-1322483, and DOD-W911NF-13-1-0159.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2016.MAR.E28.1