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111.
112.
The entropy of a system gives a powerful insight into its microscopic degrees of freedom; however, standard experimental ways of measuring entropy through heat capacity are hard to apply to nanoscale systems, as they require the measurement of increasingly small amounts of heat. Two alternative entropy measurement methods have been recently proposed for nanodevices: through charge balance measurements and transport properties. We describe a self-consistent thermodynamic framework for applying thermodynamic relations to few-electron nanodevices—small systems, where fluctuations in particle number are significant, whilst highlighting several ongoing misconceptions. We derive a relation (a consequence of a Maxwell relation for small systems), which describes both existing entropy measurement methods as special cases, while also allowing the experimentalist to probe the intermediate regime between them. Finally, we independently prove the applicability of our framework in systems with complex microscopic dynamics—those with many excited states of various degeneracies—from microscopic considerations. 相似文献
113.
Quantum phase transition and Coulomb blockade effect in triangular quantum dots with interdot capacitive and tunnel couplings 下载免费PDF全文
The quantum phase transition and the electronic transport in a triangular quantum dot system are investigated using the numerical renormalization group method.We concentrate on the interplay between the interdot capacitive coupling V and the interdot tunnel coupling t.For small t,three dots form a local spin doublet.As t increases,due to the competition between V and t,there exist two first-order transitions with phase sequence spin-doublet-magnetic frustration phase-orbital spin singlet.When t is absent,the evolutions of the total charge on the dots and the linear conductance are of the typical Coulomb-blockade features with increasing gate voltage.While for sufficient t,the antiferromagnetic spin correlation between dots is enhanced,and the conductance is strongly suppressed for the bonding state is almost doubly occupied. 相似文献
114.
Kaiyuan Ni Taokun Luo Guangxu Lan August Culbert Yang Song Tong Wu Xiaomin Jiang Wenbin Lin 《Angewandte Chemie (International ed. in English)》2020,59(3):1108-1112
Checkpoint blockade immunotherapy (CBI) awakes a host innate immune system and reactivates cytotoxic T cells to elicit durable response in some cancer patients. Now, a cationic nanoscale metal–organic framework, W‐TBP, is used to facilitate tumor antigen presentation by enabling immunogenic photodynamic therapy (PDT) and promoting the maturation of dendritic cells (DCs). Comprised of dinuclear WVI secondary building units and photosensitizing 5,10,15,20‐tetra(p‐benzoato)porphyrin (TBP) ligands, cationic W‐TBP mediates PDT to release tumor associated antigens and delivers immunostimulatory CpG oligodeoxynucleotides to DCs. The enhanced antigen presentation synergizes with CBI to expand and reinvigorate cytotoxic T cells, leading to superb anticancer efficacy and robust abscopal effects with >97 % tumor regression in a bilateral breast cancer model. 相似文献
115.
C.P. Michael M. Kataoka C.J.B. Ford G. Faini D. Mailly M.Y. Simmons D.A. Ritchie 《Physica E: Low-dimensional Systems and Nanostructures》2006,34(1-2):195
Source-drain bias measurements of transport across quantum antidots reveal a ladder of excited states analogous to the excitation spectrum of quantum dots. The antidot excitation spectrum provides an unambiguous method of determining the Coulomb-blockade charging energy and the energy difference between antidot single-particle states. The energy-level spacings and the presence of strong Kondo resonances in this regime cannot be explained within a non-interacting model. 相似文献
116.
T.A. Knuuttila K.K. Nummila W. Yao J.P. Kauppinen J.P. Pekola 《Physica E: Low-dimensional Systems and Nanostructures》1998,3(4):323
We investigate electron thermalization of tunnel junction arrays installed in a powerful dilution refrigerator whose mixing chamber can produce lattice temperatures down to 3 mK. The on-chip Coulomb blockade thermometers (CBT) against other thermometers at the mixing chamber provide direct information on the thermal equilibrium between the electronic system and the refrigerator. We can detect and discriminate between the heat load delivered through the wiring and that produced by the bias current of the CBT-measurement. The basic heat leak limits the minimum of the electronic temperature to slightly below 20 mK. 相似文献
117.
M. G. Ancona 《Superlattices and Microstructures》1996,20(4):461-472
The possibility of using single-electron digital circuits (SEDCs) to achieve ultra-high performance digital signal processing is explored. SEDCs are highly-scalable Coulomb blockade-based circuits that operate in the discrete limit where bits are represented by single electrons. Such circuits are well-suited to implementing bit-level systolic processing algorithms because the local connectivity of systolic arrays translates into locally-interconnected hardware. By relieving interconnect bandwidth limitations this enables circuits that can fully exploit the extreme scaling possible with the single-electron devices. Errors associated with co-tunneling, thermal fluctuations, etc. are an important issue in single-electron circuits, especially for a digital application. The systolic arrays are, however, amenable to simple error-correction techniques which may make computing with these unreliable components possible. Nevertheless, it must be emphasized that realization of these complex circuits depends on tremendous advances in fabrication technology, particularly to meet their stringent uniformity requirements. 相似文献
118.
We introduce the ab-initio framework for zigzag-edged graphene fragment based single-electron transistor (SET) operating in the Coulomb blockade regime. Graphene is modeled using the density-functional theory and the environment is described by a continuum model. The interaction between graphene and the SET environment is treated self-consistently through the Poisson equation. We calculate the charging energy as a function of an external gate potential, and from this we obtain the charge stability diagram. Specifically, the importance of including re-normalization of the charge states due to the polarization of the environment has been demonstrated. 相似文献
119.
Coherent control of OH‐free radicals interacting with the spin‐triplet state of a DNA molecule is investigated. A model Hamiltonian for molecular spin singlet‐triplet resonance is developed. We illustrate that the spin‐triplet state in DNA molecules can be efficiently populated, as the spin‐injection rate can be tuned to be orders of magnitudes greater than the decay rate due to small spin‐orbit coupling in organic molecules. Owing to the nano‐second life‐time of OH free radicals, a non‐equilibrium free energy barrier induced by the injected spin triplet state that lasts approximately longer than one‐micro second in room temperature can efficiently block the initial Hydrogen abstraction and DNA damage. For a direct demonstration of the spin‐blockade effect, a molecular simulation based on an ab‐initio Car‐Parrinello molecular dynamics is deployed. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献
120.
The electron tunneling through single self-assembled InAs dot in split-gate δ-doped channel transistor structure is reported for the first time. In the nearly pinch-off conditions, the channel current was found to manifest itself single-electron tunneling through a self-assembled InAs dot buried in adjacent to the channel. The line shape of the single-electron tunneling current through a single InAs dot is discussed. 相似文献