1
|
Liu D, Li L, Jiang N. Nanoscale Chemical Probing of Metal-Supported Ultrathin Ferrous Oxide via Tip-Enhanced Raman Spectroscopy and Scanning Tunneling Microscopy. CHEMICAL & BIOMEDICAL IMAGING 2024; 2:345-351. [PMID: 38817320 PMCID: PMC11134605 DOI: 10.1021/cbmi.4c00015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/04/2024] [Accepted: 03/11/2024] [Indexed: 06/01/2024]
Abstract
Metal-supported ultrathin ferrous oxide (FeO) has attracted immense interest in academia and industry due to its widespread applications in heterogeneous catalysis. However, chemical insight into the local structural characteristics of FeO, despite its critical importance in elucidating structure-property relationships, remains elusive. In this work, we report the nanoscale chemical probing of gold (Au)-supported ultrathin FeO via ultrahigh-vacuum tip-enhanced Raman spectroscopy (UHV-TERS) and scanning tunneling microscopy (STM). For comparative analysis, single-crystal Au(111) and Au(100) substrates are used to tune the interfacial properties of FeO. Although STM images show distinctly different moiré superstructures on FeO nanoislands on Au(111) and Au(100), TERS demonstrates the same chemical nature of FeO by comparable vibrational features. In addition, combined TERS and STM measurements identify a unique wrinkled FeO structure on Au(100), which is correlated to the reassembly of the intrinsic Au(100) surface reconstruction due to FeO deposition. Beyond revealing the morphologies of ultrathin FeO on Au substrates, our study provides a thorough understanding of the local interfacial properties and interactions of FeO on Au, which could shed light on the rational design of metal-supported FeO catalysts. Furthermore, this work demonstrates the promising utility of combined TERS and STM in chemically probing the structural properties of metal-supported ultrathin oxides on the nanoscale.
Collapse
Affiliation(s)
- Dairong Liu
- Department
of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, United States
| | - Linfei Li
- Department
of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, United States
| | - Nan Jiang
- Department
of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, United States
- Department
of Physics, University of Illinois Chicago, Chicago, Illinois 60607, United States
| |
Collapse
|
2
|
Allerbeck J, Kuttruff J, Bobzien L, Huberich L, Tsarev M, Schuler B. Efficient and Continuous Carrier-Envelope Phase Control for Terahertz Lightwave-Driven Scanning Probe Microscopy. ACS PHOTONICS 2023; 10:3888-3895. [PMID: 38027247 PMCID: PMC10655500 DOI: 10.1021/acsphotonics.3c00555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Indexed: 12/01/2023]
Abstract
The fundamental understanding of quantum dynamics in advanced materials requires precise characterization at the limit of spatiotemporal resolution. Ultrafast scanning tunneling microscopy is a powerful tool combining the benefits of picosecond time resolution provided by single-cycle terahertz (THz) pulses and atomic spatial resolution of a scanning tunneling microscope (STM). For the selective excitation of localized electronic states, the transient field profile must be tailored to the energetic structure of the system. Here, we present an advanced THz-STM setup combining multi-MHz repetition rates, strong THz near fields, and continuous carrier-envelope phase (CEP) control of the transient waveform. In particular, we employ frustrated total internal reflection as an efficient and cost-effective method for precise CEP control of single-cycle THz pulses with >60% field transmissivity, high pointing stability, and continuous phase shifting of up to 0.75 π in the far and near field. Efficient THz generation and dispersion management enable peak THz voltages at the tip-sample junction exceeding 20 V at 1 MHz and 1 V at 41 MHz. The system comprises two distinct THz generation arms, which facilitate individual pulse shaping and amplitude modulation. This unique feature enables the flexible implementation of various THz pump-probe schemes, thereby facilitating the study of electronic and excitonic excited-state propagation in nanostructures and low-dimensional materials systems. Scalability of the repetition rate up to 41 MHz, combined with a state-of-the-art low-temperature STM, paves the way toward the investigation of dynamical processes in atomic quantum systems at their native length and time scales.
Collapse
Affiliation(s)
- Jonas Allerbeck
- nanotech@surfaces
Laboratory, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Joel Kuttruff
- Department
of Physics, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Laric Bobzien
- nanotech@surfaces
Laboratory, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Lysander Huberich
- nanotech@surfaces
Laboratory, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Maxim Tsarev
- Department
of Physics, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Bruno Schuler
- nanotech@surfaces
Laboratory, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| |
Collapse
|
3
|
Liang K, Bi L, Zhu Q, Zhou H, Li S. Ultrafast Dynamics Revealed with Time-Resolved Scanning Tunneling Microscopy: A Review. ACS APPLIED OPTICAL MATERIALS 2023; 1:924-938. [PMID: 37260467 PMCID: PMC10227725 DOI: 10.1021/acsaom.2c00169] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/23/2023] [Indexed: 06/02/2023]
Abstract
A scanning tunneling microscope (STM) capable of performing pump-probe spectroscopy integrates unmatched atomic-scale resolution with high temporal resolution. In recent years, the union of electronic, terahertz, or visible/near-infrared pulses with STM has contributed to our understanding of the atomic-scale processes that happen between milliseconds and attoseconds. This time-resolved STM (TR-STM) technique is evolving into an unparalleled approach for exploring the ultrafast nuclear, electronic, or spin dynamics of molecules, low-dimensional structures, and material surfaces. Here, we review the recent advancements in TR-STM; survey its application in measuring the dynamics of three distinct systems, nucleus, electron, and spin; and report the studies on these transient processes in a series of materials. Besides the discussion on state-of-the-art techniques, we also highlight several emerging research topics about the ultrafast processes in nanoscale objects where we anticipate that the TR-STM can help broaden our knowledge.
Collapse
Affiliation(s)
- Kangkai Liang
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Liya Bi
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Qingyi Zhu
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
| | - Hao Zhou
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Shaowei Li
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| |
Collapse
|