1
|
Lin YH, Hsu CH, Jang I, Chen CJ, Chiu PM, Lin DS, Wu CT, Chuang FC, Chang PY, Hsu PJ. Proximity-Effect-Induced Anisotropic Superconductivity in a Monolayer Ni-Pb Binary Alloy. ACS APPLIED MATERIALS & INTERFACES 2022; 14:23990-23997. [PMID: 35575457 DOI: 10.1021/acsami.2c03034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A proximity effect facilitates the penetration of Cooper pairs that permits superconductivity in a normal metal, offering a promising approach to turn heterogeneous materials into superconductors and develop exceptional quantum phenomena. Here, we have systematically investigated proximity-induced anisotropic superconductivity in a monolayer Ni-Pb binary alloy by combining scanning tunneling microscopy/spectroscopy (STM/STS) with theoretical calculations. By means of high-temperature growth, the ( 3 3 × 3 3 ) R 30 o Ni-Pb surface alloy has been fabricated on Pb(111) and the appearance of a domain boundary as well as a structural phase transition can be deduced from a half-unit-cell lattice displacement. Given the high spatial and energy resolution, tunneling conductance (dI/dU) spectra have resolved the reduced but anisotropic superconducting gap ΔNiPb ≈ 1.0 meV, in stark contrast to the isotropic ΔPb ≈ 1.3 meV. In addition, the higher density of states at the Fermi energy (D(EF)) of the Ni-Pb surface alloy results in an enhancement of coherence peak height. According to the same Tc ≈ 7.1 K with Pb(111) from the temperature-dependent ΔNiPb and the short decay length Ld ≈ 3.55 nm from the spatially monotonic decrease of ΔNiPb, both results are supportive of a proximity-induced superconductivity. Despite a lack of a bulk counterpart, the atomically thick Ni-Pb bimetallic compound opens a pathway to engineer superconducting properties down to the two-dimensional limit, giving rise to the emergence of anisotropic superconductivity via a proximity effect.
Collapse
Affiliation(s)
- Yen-Hui Lin
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Chia-Hsiu Hsu
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| | - Iksu Jang
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Chia-Ju Chen
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Pok-Man Chiu
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Deng-Sung Lin
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Chien-Te Wu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 300093, Taiwan
| | - Feng-Chuan Chuang
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| | - Po-Yao Chang
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Pin-Jui Hsu
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 300044, Taiwan
| |
Collapse
|
2
|
Liao B, Maznev AA, Nelson KA, Chen G. Photo-excited charge carriers suppress sub-terahertz phonon mode in silicon at room temperature. Nat Commun 2016; 7:13174. [PMID: 27731406 PMCID: PMC5064017 DOI: 10.1038/ncomms13174] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 09/05/2016] [Indexed: 11/09/2022] Open
Abstract
There is a growing interest in the mode-by-mode understanding of electron and phonon transport for improving energy conversion technologies, such as thermoelectrics and photovoltaics. Whereas remarkable progress has been made in probing phonon-phonon interactions, it has been a challenge to directly measure electron-phonon interactions at the single-mode level, especially their effect on phonon transport above cryogenic temperatures. Here we use three-pulse photoacoustic spectroscopy to investigate the damping of a single sub-terahertz coherent phonon mode by free charge carriers in silicon at room temperature. Building on conventional pump-probe photoacoustic spectroscopy, we introduce an additional laser pulse to optically generate charge carriers, and carefully design temporal sequence of the three pulses to unambiguously quantify the scattering rate of a single-phonon mode due to the electron-phonon interaction. Our results confirm predictions from first-principles simulations and indicate the importance of the often-neglected effect of electron-phonon interaction on phonon transport in doped semiconductors.
Collapse
Affiliation(s)
- Bolin Liao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A. A. Maznev
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Keith A. Nelson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Gang Chen
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| |
Collapse
|
3
|
Bergk B, Petzold V, Rosner H, Drechsler SL, Bartkowiak M, Ignatchik O, Bianchi AD, Sheikin I, Canfield PC, Wosnitza J. Anisotropic multiband many-body interactions in LuNi2B2C. PHYSICAL REVIEW LETTERS 2008; 100:257004. [PMID: 18643696 DOI: 10.1103/physrevlett.100.257004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Indexed: 05/26/2023]
Abstract
We present a comprehensive de Haas-van Alphen study on the nonmagnetic borocarbide superconductor LuNi2B2C. The analysis of the angular-dependent effective masses for different bands in combination with full-potential density functional calculations allowed us to determine the mass-enhancement factors, lambda, for the different electronic bands and their wave-vector dependences. Our data clearly show the anisotropic multiband character of the superconductivity in LuNi2B2C.
Collapse
Affiliation(s)
- B Bergk
- Hochfeld-Magnetlabor Dresden (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Baba T, Yokoya T, Tsuda S, Kiss T, Shimojima T, Ishizaka K, Takeya H, Hirata K, Watanabe T, Nohara M, Takagi H, Nakai N, Machida K, Togashi T, Watanabe S, Wang XY, Chen CT, Shin S. Bulk electronic structure of the antiferromagnetic superconducting phase in ErNi2B2C. PHYSICAL REVIEW LETTERS 2008; 100:017003. [PMID: 18232808 DOI: 10.1103/physrevlett.100.017003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Indexed: 05/25/2023]
Abstract
We have performed temperature- (T-)dependent laser-photoemission spectroscopy of the antiferromagnetic (AF) superconductor ErNi2B2C to study the electronic-structure evolution reflecting the interplay between antiferromagnetism and superconductivity. The spectra at the superconducting (SC) phase show a very broad spectral shape. A T-dependent SC gap shows a sudden deviation from the BCS prediction just below TN. This observation can be explained well by the theoretical model and thus represents the characteristic bulk electronic structure of the AF SC phase for the first time.
Collapse
Affiliation(s)
- T Baba
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Chu RM, Chen QY, Chu WK. Angular-dependent I-V characteristics in borocarbide superconductor YNi(2)B(2)C. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2006; 18:4085-4092. [PMID: 21690760 DOI: 10.1088/0953-8984/18/16/015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present angular-dependent current-voltage (I-V) measurements in borocarbide YNi(2)B(2)C single crystals near the vortex-glass irreversible line. External magnetic fields are applied along the angle θ with respect to the c-axis. The nonlinear I-V curves reveal scaling behaviour near the transition. Using the scaling analysis, the relevant critical exponents and vortex transition temperatures are determined for all orientations. The data agrees well with the vortex-glass (VG) model. No evidence was found that supports the existence of a Bose-glass (BG) type of transition.
Collapse
Affiliation(s)
- R M Chu
- Bio-Nano Computational Laboratory (RCMI-NCRR) and Physics Department, Texas Southern University, Houston, TX 77004, USA
| | | | | |
Collapse
|
6
|
Raychaudhuri P, Jaiswal-Nagar D, Sheet G, Ramakrishnan S, Takeya H. Evidence of gap anisotropy in superconducting YNi2B2C using directional point-contact spectroscopy. PHYSICAL REVIEW LETTERS 2004; 93:156802. [PMID: 15524920 DOI: 10.1103/physrevlett.93.156802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Indexed: 05/24/2023]
Abstract
We present a study of the anisotropy in the superconducting energy gap in a single crystal of YNi2B2C (T(c) approximately 14.6 K) using directional point-contact spectroscopy. The superconducting energy gap at 2.7 K, when measured for I||c, is 4.5 times larger than that for I||a. The energy gaps in the two directions also have different temperature dependences. Our results support a scenario with s + g like symmetry.
Collapse
Affiliation(s)
- P Raychaudhuri
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India.
| | | | | | | | | |
Collapse
|