ترغب بنشر مسار تعليمي؟ اضغط هنا

Energy Scales of the Doped Anderson Lattice Model

60   0   0.0 ( 0 )
 نشر من قبل Hanhim Kang
 تاريخ النشر 2019
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

This paper explores the energy scales of the doped Anderson lattice model using dynamical mean-field theory (DMFT), using a continuous-time Quantum Monte Carlo (CTQMC) impurity solver. We show that the low temperature properties of the lattice can not be scaled using the single ion local Kondo temperature $T_K$ but instead are governed by a doping-dependent coherence temperature $T*$ which can be used to scale the temperature dependence of the spectral function, transport properties, and entropy. At half filling $T*$ closely approximates the single ion $T_K$, but as the filling $n_c$ is reduced to zero, $T*$ also vanishes. The coherence temperature $T*$ is shown to play a role of effective impurity Kondo temperature in the lattice model, and physical observables show significant evolution at $T*$. In the DMFT framework, we showed that the hybridization strength of the effective impurity model is qualitatively affected by the doping level, and determines $T*$ in the lattice model.

قيم البحث

اقرأ أيضاً

We derive the disorder vs. doping phase diagram of the doped Hubbard model via Dynamical Mean Field Theory combined with Typical Medium Theory, which allows the description of both Mott (correlation driven) and Anderson (disorder driven) metal-insula tor transitions. We observe a transition from a metal to an Anderson-Mott insulator for increasing disorder strength at all interactions. In the weak correlation regime and rather small doping, the Anderson-Mott insulator displays properties which are alike to the ones found at half-filling. In particular, this phase is characterized by the presence of empty sites. If we further increase either the doping or the correlation however, an Anderson-Mott phase of different kind arises for sharply weaker disorder strength. This phase occupies the largest part of the phase diagram in the strong correlation regime, and is characterized by the absence of the empty sites.
86 - S. Burdin , V. Zlatic 2008
The thermodynamic and transport properties of intermetallic compounds with Ce, Eu, and Yb ions are discussed using the periodic Anderson model with an infinite correlation between $f$ electrons. The slave boson solution of the periodic model shows th at the Fermi liquid scale T$_0$ and the Kondo scale T$_K$ depend on the shape of the conduction electrons density of states ($c$ DOS) in the vicinity of the chemical potential, that the details of the band structure determine the ratio T$_0$/T$_K$, and that the crossover between the high- and low-temperature regimes in ordered compounds is system-dependent. A sharp peak in the $c$ DOS yields T$_0 ll$T$_K$ and explains the slow crossover observed in YbAl$_3$ or YbMgCu$_4$. A minimum in the $c$ DOS yields T$_0 gg$T$_K$, which leads to the abrupt transition between the high- and low-temperature regimes in YbInCu$_4$. In the case of CeCu$_2$Ge$_2$ and CeCu$_2$Si$_2$, where T$_0 simeq T_K$, the slave boson solution explains the pressure experiments which reveal sharp peaks in the T$^2$ coefficient of the electrical resistance, $A=rho(T)/T^2$, and the residual resistance. These peaks are due to the change in the degeneracy of the $f$ states induced by the applied pressure. We show that the low-temperature response of the periodic Anderson model can be enhanced (or reduced) with respect to the predictions based on the single-impurity models that give the same high-temperature behavior.
We study the interplay of disorder and correlation in the one-dimensional hole-doped Hubbard-model with disorder (Anderson-Hubbard model) by using the density-matrix renormalization group method. Concentrating on the doped-hole density profile, we fi nd in a large $U/t$ regime that the clean system exhibits a simple fluid-like behavior whereas finite disorders create locally Mott regions which expand their area with increasing the disorder strength contrary to the ordinary sense. We propose that such an anomalous Mott phase formation assisted by disorder is observable in atomic Fermi gases by setup of the box shape trap.
93 - M. Jiang , Yi-feng Yang 2017
We report a Dynamical Cluster Approximation (DCA) investigation of the doped periodic Anderson model (PAM) to explain the universal scaling in the Knight shift anomaly predicted by the phenomenological two-fluid model and confirmed in many heavy-ferm ion compounds. We calculate the quantitative evolution of the orbital-dependent magnetic susceptibility and reproduce correctly the two-fluid prediction in a large range of doping and hybridization. Our results confirm the presence of a temperature/energy scale $T^{ast}$ for the universal scaling and show distinctive behavors of the Knight shift anomaly in response to other orders at low temperatures. However, comparison with the temperature evolution of the calculated resistivity and quasiparticle spectral peak indicates a different characteristic temperature from $T^*$, in contradiction with the experimental observation in CeCoIn$_5$ and other compounds. This reveals a missing piece in the current model calculations in explaining the two-fluid phenomenology.
We present benchmark calculations of the Anderson lattice model based on the recently-developed ghost Gutzwiller approximation. Our analysis shows that, in some parameters regimes, the predictions of the standard Gutzwiller approximation can be incor rect by orders of magnitude for this model. We show that this is caused by the inability of this method to describe simultaneously the Mott physics and the hybridization between correlated and itinerant degrees of freedom (whose interplay often governs the metal-insulator transition in real materials). Finally, we show that the ghost Gutzwiller approximation solves this problem, providing us with results in remarkable agreement with dynamical mean field theory throughout the entire phase diagram, while being much less computationally demanding. We provide an analytical explanation of these findings and discuss their implications within the context of ab-initio computation of strongly-correlated matter.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا