scholarly journals Graphene-Based Topological Insulator with an Intrinsic Bulk Band Gap above Room Temperature

Nano Letters ◽  
2013 ◽  
Vol 13 (12) ◽  
pp. 6251-6255 ◽  
Author(s):  
Liangzhi Kou ◽  
Binghai Yan ◽  
Feiming Hu ◽  
Shu-Chun Wu ◽  
Tim O. Wehling ◽  
...  
Keyword(s):  
Band Gap ◽  
Topological Insulator ◽  
Room Temperature ◽  
Bulk Band

OPTICAL ABSORPTION BEHAVIOR OF Co (II) ION DOPED PVA ASSISTED CdSe NANOPARTICLES

2013 ◽  
Vol 22 ◽  
pp. 346-350
Author(s):  
K. RAVINDRANADH ◽  
R. V. S. S. N. RAVIKUMAR ◽  
M. C. RAO
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Urbach Energy ◽  
Wavelength Region ◽  
Wide Band ◽  
Cdse Nanoparticles ◽  
Poly Vinyl Alcohol ◽  
Wide Band Gap ◽  
Direct Band ◽  
Bulk Band

CdSe is an important II-VI, n-type direct band gap semiconductor with wide band gap (bulk band gap of 2.6 eV) and an attractive host for the development of doped nanoparticles. Poly vinyl alcohol (PVA) is used as a capping agent to stabilize the CdSe nanoparticles. The optical properties of Co (II) ion doped PVA capped CdSe nanoparticles grown at room temperature are studied in the wavelength region of 200-1400 nm. The spectrum of Co (II) ion doped PVA capped CdSe nanoparticles exhibit five bands at 1185, 620, 602, 548 and 465 nm (8437, 16125, 16607, 18243 and 21499 cm-1). The bands observed at 1185, 548 and 465 nm are correspond to the three spin allowed transitions 4T1g (F) → 4T2g (F), 4T1g (F) → 4A2g (F) and 4T1g (F) → 4T1g (P) respectively. The other bands observed at 602 nm and 620 nm are assigned to spin forbidden transitions 4T1g (F) → 2T2g (G), 4T1g (F) → 2T1g (G) . The small value of the Urbach energy indicates greater stability of the prepared sample.

scholarly journals Below bulk-band-gap photoluminescence at room temperature from heavily P- and B-doped Si nanocrystals

2003 ◽  
Vol 94 (3) ◽  
pp. 1990-1995 ◽  
Author(s):  
Minoru Fujii ◽  
Kimiaki Toshikiyo ◽  
Yuji Takase ◽  
Yasuhiro Yamaguchi ◽  
Shinji Hayashi
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Si Nanocrystals ◽  
Bulk Band

scholarly journals Manipulation of Topological States and the Bulk Band Gap Using Natural Heterostructures of a Topological Insulator

2012 ◽  
Vol 109 (23) ◽  
Author(s):  
K. Nakayama ◽  
K. Eto ◽  
Y. Tanaka ◽  
T. Sato ◽  
S. Souma ◽  
...  
Keyword(s):  
Band Gap ◽  
Topological Insulator ◽  
Topological States ◽  
Bulk Band

Quantum spin Hall insulator BiXH (XH = OH, SH) monolayers with a large bulk band gap

2018 ◽  
Vol 20 (19) ◽  
pp. 13632-13636 ◽  
Author(s):  
Xing-Kai Hu ◽  
Ji-Kai Lyu ◽  
Chang-Wen Zhang ◽  
Pei-Ji Wang ◽  
Wei-Xiao Ji ◽  
...  
Keyword(s):  
Band Gap ◽  
Topological Insulators ◽  
Room Temperature ◽  
Quantum Spin ◽  
Two Dimensional ◽  
Spintronic Devices ◽  
Large Bulk ◽  
Bulk Band ◽  
Quantum Spin Hall

A large bulk band gap is critical for the application of two-dimensional topological insulators (TIs) in spintronic devices operating at room temperature.

scholarly journals Enhanced surface state protection and band gap in the topological insulator PbBi4Te4S3

2018 ◽  
Vol 2 (10) ◽  
Author(s):  
K. Sumida ◽  
T. Natsumeda ◽  
K. Miyamoto ◽  
I. V. Silkin ◽  
K. Kuroda ◽  
...  
Keyword(s):  
Band Gap ◽  
Topological Insulator ◽  
Surface State ◽  
Enhanced Surface ◽  
State Protection

scholarly journals Observation and control of the weak topological insulator state in ZrTe5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng Zhang ◽  
Ryo Noguchi ◽  
Kenta Kuroda ◽  
Chun Lin ◽  
Kaishu Kawaguchi ◽  
...  
Keyword(s):  
Band Gap ◽  
Topological Insulator ◽  
Spin Current ◽  
Side Surface ◽  
Quantum Spin ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Dirac Semimetal ◽  
Topological States ◽  
The One ◽  
And Control

AbstractA quantum spin Hall (QSH) insulator hosts topological states at the one-dimensional (1D) edge, along which backscattering by nonmagnetic impurities is strictly prohibited. Its 3D analogue, a weak topological insulator (WTI), possesses similar quasi-1D topological states confined at side surfaces. The enhanced confinement could provide a route for dissipationless current and better advantages for applications relative to strong topological insulators (STIs). However, the topological side surface is usually not cleavable and is thus hard to observe. Here, we visualize the topological states of the WTI candidate ZrTe5 by spin and angle-resolved photoemission spectroscopy (ARPES): a quasi-1D band with spin-momentum locking was revealed on the side surface. We further demonstrate that the bulk band gap is controlled by external strain, realizing a more stable WTI state or an ideal Dirac semimetal (DS) state. The highly directional spin-current and the tunable band gap in ZrTe5 will provide an excellent platform for applications.

Electronic structure engineering of tin telluride through co-doping of bismuth and indium for high performance thermoelectrics: a synergistic effect leading to a record high room temperature ZT in tin telluride

2019 ◽  
Vol 7 (16) ◽  
pp. 4817-4821 ◽  
Author(s):  
U. Sandhya Shenoy ◽  
D. Krishna Bhat
Keyword(s):  
Electronic Structure ◽  
Synergistic Effect ◽  
Band Gap ◽  
High Performance ◽  
Room Temperature ◽  
Band Offset ◽  
Valence Band Offset ◽  
Co Doping ◽  
Tin Telluride ◽  
Structure Engineering

Resonance states due to Bi and In co-doping, band gap enlargement, and a reduced valence-band offset in SnTe lead to a record high room-temperature ZT.

scholarly journals Gold-Hyperdoped Germanium with Room-Temperature Sub-Band-Gap Optoelectronic Response

2020 ◽  
Vol 14 (6) ◽  
Author(s):  
Hemi H. Gandhi ◽  
David Pastor ◽  
Tuan T. Tran ◽  
S. Kalchmair ◽  
L.A. Smilie ◽  
...  
Keyword(s):  
Band Gap ◽  
Room Temperature

scholarly journals Room temperature electrically pumped topological insulator lasers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jae-Hyuck Choi ◽  
William E. Hayenga ◽  
Yuzhou G. N. Liu ◽  
Midya Parto ◽  
Babak Bahari ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Room Temperature ◽  
Phase Locking ◽  
Quantum Spin ◽  
Single Frequency ◽  
Laser Array ◽  
Quantum Spin Hall Effect ◽  
Electrically Pumped ◽  
Spatially Extended ◽  
Synthetic Gauge Fields

AbstractTopological insulator lasers (TILs) are a recently introduced family of lasing arrays in which phase locking is achieved through synthetic gauge fields. These single frequency light source arrays operate in the spatially extended edge modes of topologically non-trivial optical lattices. Because of the inherent robustness of topological modes against perturbations and defects, such topological insulator lasers tend to demonstrate higher slope efficiencies as compared to their topologically trivial counterparts. So far, magnetic and non-magnetic optically pumped topological laser arrays as well as electrically pumped TILs that are operating at cryogenic temperatures have been demonstrated. Here we present the first room temperature and electrically pumped topological insulator laser. This laser array, using a structure that mimics the quantum spin Hall effect for photons, generates light at telecom wavelengths and exhibits single frequency emission. Our work is expected to lead to further developments in laser science and technology, while opening up new possibilities in topological photonics.

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