Two-dimensional hybrid metal halide device allows control of terahertz emissions

Date:
October 1, 2021
Source:
North Carolina State University
Summary:
Researchers have utilized two-dimensional hybrid metal halides in
a device that allows directional control of terahertz radiation
generated by a spintronic scheme. The device has better signal
efficiency than conventional terahertz generators, and is thinner,
lighter and less expensive to produce.



FULL STORY ========================================================================== Researchers have utilized two-dimensional hybrid metal halides in a
device that allows directional control of terahertz radiation generated
by a spintronic scheme. The device has better signal efficiency than conventional terahertz generators, and is thinner, lighter and less
expensive to produce.


========================================================================== Terahertz (THz) refers to the part of the electromagnetic spectrum (i.e., frequencies between 100 GHz and 10 THz) between microwave and optical, and
THz technologies have shown promise for applications ranging from faster computing and communications to sensitive detection equipment. However, creating reliable THz devices has been challenging due to their size,
cost and energy conversion inefficiency.

"Ideally, THz devices of the future should be lightweight, low-cost and
robust, but that has been difficult to achieve with current materials,"
says Dali Sun, assistant professor of physics at North Carolina State University and co- corresponding author of the work. "In this work,
we found that a 2D hybrid metal halide commonly used in solar cells
and diodes, in conjunction with spintronics, may meet several of these requirements." The 2D hybrid metal halide in question is a popular and commercially available synthetic hybrid semiconductor: butyl ammonium
lead iodine. Spintronics refers to controlling the spin of an electron,
rather than just using its charge, in order to create energy.

Sun and colleagues from Argonne National Laboratories, the University of
North Carolina at Chapel Hill and Oakland University created a device
that layered the 2D hybrid metal halides with a ferromagnetic metal,
then excited it with a laser, creating an ultrafast spin current that
in turn generated THz radiation.

The team found that not only did the 2D hybrid metal halide device
outperform larger, heavier and more expensive to produce THz emitters
currently in use, they also found that the 2D hybrid metal halide's
properties allowed them to control the direction of the THz transmission.

"Traditional terahertz transmitters were based upon ultrafast
photocurrent," Sun says. "But spintronic-generated emissions produce a
wider bandwidth of THz frequency, and the direction of the THz emission
can be controlled by modifying the speed of the laser pulse and the
direction of the magnetic field, which in turn affects the interaction
of magnons, photons, and spins and allows us directional control."
Sun believes that this work could be a first step in exploring 2D hybrid
metal halide materials generally as potentially useful in other spintronic applications.

"The 2D hybrid metal halide-based device used here is smaller and more economical to produce, is robust and works well at higher temperatures,"
Sun says. "This suggests that 2D hybrid metal halide materials may prove superior to the current conventional semiconductor materials for THz applications, which require sophisticated deposition approaches that
are more susceptible to defects.

"We hope that our research will launch a promising testbed for designing
a wide variety of low-dimensional hybrid metal halide materials for
future solution- based spintronic and spin-optoelectronic applications."
The work appears in Nature Communications and is supported by the
National Science Foundation under grant ECCS-1933297. Postdoctoral
researcher Kankan Cong of Argonne National Laboratory, former NC State
graduate student Eric Vetter of North Carolina State University, and postdoctoral researcher Liang Yan of UNC-CH are co-first authors. Haiden
Wen, physicist at Argonne National Laboratory, Wei You, professor
of chemistry at UNC-CH and Wei Zhang, associate professor at Oakland University, are co-corresponding authors of the research.

========================================================================== Story Source: Materials provided by
North_Carolina_State_University. Original written by Tracey Peake. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kankan Cong, Eric Vetter, Liang Yan, Yi Li, Qi Zhang, Yuzan Xiong,
Hongwei Qu, Richard D. Schaller, Axel Hoffmann, Alexander F. Kemper,
Yongxin Yao, Jigang Wang, Wei You, Haidan Wen, Wei Zhang, Dali Sun.

Coherent control of asymmetric spintronic terahertz emission from
two- dimensional hybrid metal halides. Nature Communications,
2021; 12 (1) DOI: 10.1038/s41467-021-26011-6 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211001152714.htm

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