New spectroscopy approach measures the properties of simply the topmost atomic layer of supplies


Nov 12, 2022

(Nanowerk Information) Physicists at The College of Texas at Arlington have developed a brand new approach that may measure the properties of the topmost atomic layer of supplies with out together with data from the underlying layers. Researchers from the Positron Lab within the UTA Division of Physics utilized a course of known as auger-mediated positron sticking (AMPS) to develop a novel spectroscopic device to measure the digital construction of the floor of supplies selectively. A brand new article revealed within the journal Bodily Overview Letters (“Photoemission Spectroscopy Utilizing Digital Photons Emitted by Positron Sticking: A Complementary Probe for Prime-Layer Floor Digital Constructions”), particulars the brand new approach. As well as, the net journal Physics revealed a Viewpoint article on the publication, titled “Spectroscopy That Doesn’t Scratch the Floor”, which explains why the paper is essential to the sector. Viewpoint articles are commissioned by PRL editors for papers they imagine will draw broad curiosity. Alex Fairchild, postdoctoral scholar within the Positron Lab, is the research’s lead creator. Co-authors embrace Varghese Chirayath, assistant professor of analysis; Randall Gladen, postdoctoral researcher; Ali Koymen, professor of physics; and Alex Weiss, professor and chair of the UTA Division of Physics. Bernardo Barbiellini, professor of physics at LUT College in Finland, additionally contributed to the challenge. The AMPS course of, through which positrons (antimatter of electrons) stick on to surfaces adopted by electron emission, was first noticed and described by Saurabh Mukherjee, a graduate pupil, together with Weiss and different colleagues, in 2010 at UTA. These outcomes have been revealed in a paper in PRL (“Auger-Mediated Sticking of Positrons to Surfaces: Proof for a Single-Step Transition from a Scattering State to a Floor Picture Potential Sure State”). “Alex (Fairchild) and Varghese found out tips on how to use this phenomenon that we found in 2010 to measure the highest layer and get details about the digital construction and the habits of the electrons within the prime layer,” Weiss stated. “That can decide a cloth’s many properties, together with conductivity, and may have essential implications for constructing gadgets.” Fairchild stated the AMPS course of is exclusive as a result of it makes use of digital photons to measure the topmost atomic layer. “That is completely different from typical strategies like photoemission spectroscopy, the place a photon penetrates a number of layers into the majority of a cloth and due to this fact incorporates the mixed data of the floor and subsurface layers,” Fairchild stated. “Our AMPS outcomes confirmed how digital photons emitted following positron-sticking work together ideally with electrons that stretch additional into the vacuum than with electrons that have been extra localized to the atomic web site,” Chirayath stated. “Our outcomes are thus important to know how positrons work together with floor electrons and are extraordinarily essential to know different equally surface-selective, positron-based strategies.” Weiss famous that the UTA Positron Lab is at present the one place this method may have been developed, as a result of capabilities of its positron beam. “At current, UTA in all probability has the one lab on the earth that has a positron beam that may get right down to the low energies wanted to watch this phenomenon,” Weiss stated.