A New Spin-Correlated Plasmon in Novel Highly Oriented Single-Crystalline Gold Quantum Dots

Abstract

A concept of spin plasmon, a collective mode of spin-density, in strongly correlated electron systems has been proposed since the 1930s. It is expected to bridge between spintronics and plasmonics by strongly confining the photon energy in the subwavelength scale within single magnetic-domain to enable further miniaturizing devices. However, spin plasmon in strongly correlated electron systems is yet to be realized. Herein, we present a new spin correlated-plasmon at room temperature in novel Mott-like insulating highly oriented single-crystalline gold quantum-dots (HOSG-QDs). Interestingly, the spin correlated-plasmon is tunable from the infrared to visible, accompanied by spectral weight transfer yielding a large quantum absorption midgap state, disappearance of low-energy Drude response, and transparency. Supported with theoretical calculations, it occurs due to an interplay of surprisingly strong electron–electron correlations, s–p hybridization and quantum confinement in the s band. The first demonstration of the high sensitivity of spin correlated-plasmon in surface-enhanced Raman spectroscopy is also presented.

Anomalous Ferromagnetism of quasiparticle doped holes in cuprate heterostructures revealed using resonant soft X-ray magnetic scattering

“…2d, e ). Subsequent pulsed laser deposition of Au onto this LBCO surface leads to a three-dimensional (3D) growth where highly oriented single-crystalline gold quantum dots (HOSG-QDs) 32 are formed (Fig. 2f ).…”

“…HOSG-QDs further enhance the spin-triplet state, and consequently increase the ferromagnetic long-range order strength of the quasiparticle doped holes in the Cu-O plane. Note that since HOSG-QDs are ferromagnetic Mott- like insulators with a spin-polarized Mott- like state around 1.5–2 eV 32 which is located within the charge transfer gap in the cuprates 8 , 36 , spin and electronic correlations may, in turn, be enhanced between HOSG-QDs and LBCO. We further perform zero-field XMCD and find that the XMCD signals are indeed observed at both Cu L 3,2 edges and at O K edge, particularly at HDP and UHB, therefore fully supporting the findings of ferromagnetism of the doped holes in the Cu-O planes (Supplementary Fig.…”

Application of Inorganic Quantum Dots in Advanced Lithium–Sulfur Batteries

“…Quantum dots with particle size <10 nm have abundant active sites with quantum confinement effect, polar groups, high surface‐to‐volume ratios, and most are semiconductive. [ 72 , 73 , 74 , 75 ] As a result, QDs have apparent advantages over nanoparticles (>10 nm), such as good restriction of shuttling effect, excellent electrocatalytic activity, ability to buffer volume expansion, and the increased exposure of active surface area, as illustrated in Figure 2 . However, the quantum size effect would also cause the agglomeration of QDs because of their large surface energy.…”

Recent progress in quantum dots based nanocomposite electrodes for rechargeable monovalent metal-ion and lithium metal batteries

“…33,34 In this respect, the last few years have witnessed a tremendous interest in designing quantum dot based nanocomposite hybrids as electrode materials in energy storage devices. Quantum dots (QDs) with particle size <10 nm generally possess amorphous 35–38 to nanocrystalline 39–42 cores with high surface to volume ratios which hold several merits over their micron size particles in terms of enhanced active surface per unit mass for reactions (redox sites) and ion absorption, improved redox kinetics, homogeneous volume expansion/contraction during ion (de)intercalation to buffer lattice distortion, etc. In addition, QDs offer improved solid-state ion diffusion due to the shortening diffusion path, better conductivity along with the enhanced interfacial connection.…”