ICQM member Prof. Rui-Rui Du and his collaborators publish a paper on
Physical Review Letters reporting the observation of a helical Luttinger-liquid
state.
Time：2015-09-28ClickTimes：
Recently, Prof. Rui-Rui Du, and Prof. Xi Lin of ICQM, in collaboration with
Prof. G谩Bor Cs谩thy of Purdue University, discovered a new electronic state
called 鈥楬elical Luttinger liquid鈥� in InAs/GaSb quantum spin Hall edges. This is
the first experimental observations of a Luttinger -liquid state in topological
materials.
The Luttinger liquid describes one-dimensional (1D) interacting electron
system. During the past 20 years, theoretical and experimental studies of
Luttinger liquid have become a frontier of condensed matter physics. Carbon
nanotubes, as well as fractional quantum Hall edge states, have been
experimentally studied as spinful Luttinger liquid and chiral Luttinger liquid,
respectively. Topological materials have recently attracted a lot of interest in
condensed matter physics, and the quantum spin Hall insulator (QSHI) is one of
them. In 2011, Prof. Rui-Rui Du group first experimentally proved that InAs/GaSb
semiconductor quantum wells system can form a new type of QSHI (PRL 107,
136603). Recently, by ultra-low temperature transport measurements, they found
that electrons in InAs/GaSb edge states exhibit Luttinger-liquid behavior, where
the resistance of the edge states increases following a power-law with the
decreasing of temperature and bias voltage. The underlying physics, often
referred as 鈥榟elical Luttinger liquid鈥�, is quite distinct from the known types
of Luttinger liquids due to the helical nature (i.e. spin-momentum locking) of
the QSHI edge states.
The results indicate that strong electron-electron interaction effects could
play important roles in symmetry-protected topological matters, influencing
their electronic properties in a fundamental way. This finding offers a platform
for studying novel quantum correlation effects, such as e/2 charge excitations.
More importantly, interacting helical edge states coupled with superconductors
can support parafermionic modes, which are promising for topological quantum
computation.
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Schematic drawing of soliton-like excitations in the edge of InAs/GaSb
QSHI.
| The temperature and bias voltage dependence of the measured helical
edge conductance.
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The results will be published in Physical Review Letters (PRL 115, 136804) as
an Editor鈥檚 Suggestion paper. Prof. Rui-Rui Du is the corresponding author, and
Tingxin Li, his Ph. D. student at ICQM, is the first author of this paper.
The work in Peking University was supported by National Basic Research
Programs of China, and National Natural Science Foundation of China.
