3,354 research outputs found
Dynamical correlation functions and the related physical effects in three-dimensional Weyl/Dirac semimetals
We present a unified derivation of the dynamical correlation functions
including density-density, density-current and current-current, of
three-dimensional Weyl/Dirac semimetals by use of the Passarino-Veltman
reduction scheme at zero temperature. The generalized Kramers-Kronig relations
with arbitrary order of subtraction are established to verify these correlation
functions. Our results lead to the exact chiral magnetic conductivity and
directly recover the previous ones in several limits. We also investigate the
magnetic susceptibilities, the orbital magnetization and briefly discuss the
impact of electron interactions on these physical quantities within the random
phase approximation. Our work could provide a starting point for the
investigation of the nonlocal transport and optical properties due to the
higher-order spatial dispersion in three-dimensional Weyl/Dirac semimetals.Comment: 21 pages, 3+1 figures, 1 table. Accepted in PR
Entropy stabilizes floppy crystals of mobile DNA-coated colloids
Grafting linkers with open ends of complementary single-stranded DNA makes a
flexible tool to tune interactions between colloids,which facilitates the
design of complex self-assembly structures. Recently, it has been proposed to
coat colloids with mobile DNA linkers, which alleviates kinetic barriers
without high-density grafting, and also allows the design of valency without
patches.However, the self-assembly mechanism of this novel system is poorly
understood.Using a combination of theory and simulation, we obtain phase
diagrams forthe system in both two and three dimensional spaces, and find
stable floppy squareand CsCl crystals when the binding strength is strong, even
in the infinite bindingstrength limit. We demonstrate that these floppy phases
are stabilized by vibrational entropy, and "floppy" modes play an important
role in stabilizing the floppy phases for the infinite binding strength limit.
This special entropic effect in the self-assembly of mobile DNA-coated colloids
is very different from conventional molecular self-assembly, and it offers new
axis to help design novel functional materials using mobile DNA-coated
colloids.Comment: Accepted in Physical Review Letter
RKKY interaction in three-dimensional electron gases with linear spin-orbit coupling
We theoretically study the impacts of linear spin-orbit coupling (SOC) on the
Ruderman-Kittel-Kasuya-Yosida interaction between magnetic impurities in two
kinds of three-dimensional noncentrosymmetric systems. It has been found that
linear SOCs lead to the Dzyaloshinskii-Moriya interaction and the Ising
interaction, in addition to the conventional Heisenberg interaction. These
interactions possess distinct range functions from three dimensional electron
gases and Dirac/Weyl semimetals. In the weak SOC limit, the Heisenberg
interaction dominates over the other two interactions in a moderately large
region of parameters. Sufficiently strong Rashba SOC makes the
Dzyaloshinskii-Moriya interaction or the Ising interaction dominate over the
Heisenberg interaction in some regions. The change in topology of the Fermi
surface leads to some quantitative changes in periods of oscillations of range
functions. The anisotropy of Ruderman-Kittel-Kasuya-Yosida interaction in
bismuth tellurohalides family BiTe ( = Br, Cl, and I) originates from
both the specific form of Rashba SOC and the anisotropic effective mass. Our
work provides some insights into understanding observed spin textures and the
application of these materials in spintronics.Comment: 11 pages, 4 figures, Final Version in PR
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