The Role of Optical Phonon Confinement in the Infrared Dielectric Response of III–V Superlattices
- Vanderbilt University, Nashville, TN (United States)
- University of Delaware, Newark, DE (United States)
- Harvard University, Cambridge, MA (United States)
- Lund University (Sweden); Linköping University (Sweden)
- University of Nebraska, Lincoln, NE (United States)
- Lund University (Sweden); University of Nebraska, Lincoln, NE (United States)
- Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Purdue University, West Lafayette, IN (United States)
- University of California, Los Angeles, CA (United States)
- University of Delaware, Newark, DE (United States); Pennsylvania State University, University Park, PA (United States)
Polar dielectrics are key materials of interest for infrared (IR) nanophotonic applications due to their ability to host phonon-polaritons that allow for low-loss, subdiffractional control of light. The properties of phonon-polaritons are limited by the characteristics of optical phonons, which are nominally fixed for most “bulk” materials. Superlattices composed of alternating atomically thin materials offer control over crystal anisotropy through changes in composition, optical phonon confinement, and the emergence of new modes. In particular, the modified optical phonons in superlattices offer the potential for so-called crystalline hybrids whose IR properties cannot be described as a simple mixture of the bulk constituents. To date, however, studies have primarily focused on identifying the presence of new or modified optical phonon modes rather than assessing their impact on the IR response. Here, this study focuses on assessing the impact of confined optical phonon modes on the hybrid IR dielectric function in superlattices of GaSb and AlSb. Using a combination of first principles theory, Raman, FTIR, and spectroscopic ellipsometry, the hybrid dielectric function is found to track the confinement of optical phonons, leading to optical phonon spectral shifts of up to 20 cm-1. These results provide an alternative pathway toward designer IR optical materials.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- Gordon and Betty Moore Foundation (GBMF); National Science Foundation (NSF); US Air Force Office of Scientific Research (AFOSR); US Department of the Navy, Office of Naval Research (ONR); USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
- Grant/Contract Number:
- AC02-05CH11231; AC02-06CH11357; AC05-00OR22725; FG02-09ER46554
- OSTI ID:
- 2545889
- Alternate ID(s):
- OSTI ID: 2229007
- Journal Information:
- Advanced Materials, Journal Name: Advanced Materials Journal Issue: 3 Vol. 36; ISSN 0935-9648
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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