We study the low-temperature critical behavior of the one-dimensional Hubbard model near half filling caused by enhanced antiferromagnetic fluctuations. We use a mean-field-type approximation with a two-particle self-consistency renormalizing the bare interaction. It allows us to control a transition from high to low temperatures as well as from weak to strong-coupling. We show that there is a crossover temperature $T_{0}= texp{-1/Urho(0)}$ for arbitrary interaction $U>0$ and the bare density of states at the Fermi energy $rho(0)>0$. The solution at lower temperatures goes over to strong coupling and approaches a quantum critical point with the diverging staggered susceptibility and a gap in the excitation spectrum at zero temperature.
{"title":"Antiferromagnetic fluctuations in the one-dimensional Hubbard model","authors":"V. Janiš, A. Klíč, Jiawei Yan","doi":"10.1063/9.0000019","DOIUrl":"https://doi.org/10.1063/9.0000019","url":null,"abstract":"We study the low-temperature critical behavior of the one-dimensional Hubbard model near half filling caused by enhanced antiferromagnetic fluctuations. We use a mean-field-type approximation with a two-particle self-consistency renormalizing the bare interaction. It allows us to control a transition from high to low temperatures as well as from weak to strong-coupling. We show that there is a crossover temperature $T_{0}= texp{-1/Urho(0)}$ for arbitrary interaction $U>0$ and the bare density of states at the Fermi energy $rho(0)>0$. The solution at lower temperatures goes over to strong coupling and approaches a quantum critical point with the diverging staggered susceptibility and a gap in the excitation spectrum at zero temperature.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79882208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-14DOI: 10.1103/PHYSREVB.103.165408
N. Boudjada, F. Buessen, A. Paramekanti
Recent advances in ultracold atoms in optical lattices and developments in surface science have allowed for the creation of artificial lattices as well as the control of many-body interactions. Such systems provide new settings to investigate interaction-driven instabilities and non-trivial topology. In this work, we explore the interplay between molecular electric dipoles on a two-dimensional triangular lattice with fermions hopping on the dual decorated honeycomb lattice which hosts Dirac and flat band states. We show that short-range dipole-dipole interaction can lead to ordering into various stripe and vortex crystal ground states. We study these ordered states and their thermal transitions as a function of the interaction range using simulated annealing and Monte Carlo methods. For the special case of zero wavevector ferro-dipolar order, we show that incorporating dipole-electron interactions and integrating out the electrons can lead to a six-fold clock anisotropy for the dipole ordering. Finally, we discuss the impact of the various dipole orders on the electronic band structure and the local tunneling density of states. Our work may be relevant to studies of "molecular graphene" -- CO molecules arranged on the Cu(111) surface -- which have been explored using scanning tunneling spectroscopy, as well as ultracold molecule-fermion mixtures in optical lattices.
{"title":"Molecular dipoles in designer honeycomb lattices","authors":"N. Boudjada, F. Buessen, A. Paramekanti","doi":"10.1103/PHYSREVB.103.165408","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.165408","url":null,"abstract":"Recent advances in ultracold atoms in optical lattices and developments in surface science have allowed for the creation of artificial lattices as well as the control of many-body interactions. Such systems provide new settings to investigate interaction-driven instabilities and non-trivial topology. In this work, we explore the interplay between molecular electric dipoles on a two-dimensional triangular lattice with fermions hopping on the dual decorated honeycomb lattice which hosts Dirac and flat band states. We show that short-range dipole-dipole interaction can lead to ordering into various stripe and vortex crystal ground states. We study these ordered states and their thermal transitions as a function of the interaction range using simulated annealing and Monte Carlo methods. For the special case of zero wavevector ferro-dipolar order, we show that incorporating dipole-electron interactions and integrating out the electrons can lead to a six-fold clock anisotropy for the dipole ordering. Finally, we discuss the impact of the various dipole orders on the electronic band structure and the local tunneling density of states. Our work may be relevant to studies of \"molecular graphene\" -- CO molecules arranged on the Cu(111) surface -- which have been explored using scanning tunneling spectroscopy, as well as ultracold molecule-fermion mixtures in optical lattices.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91271146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-13DOI: 10.1103/PHYSREVB.103.165115
Yuya Kurebayashi, Hiroki Oshiyama, N. Shibata
We study the ground state of the one-dimensional "$t$-$J_s$-$J_{tau}$ model", which is a variant of the $t$-$J$ model with additional channel degree of freedom. The model is not only a generalization of the $t$-$J$ model but also an effective model of the two-channel Kondo lattice model in the strong coupling region. The low energy excitations and correlation functions are systematically calculated by the density matrix renormalization group (DMRG) method and the ground-state phase diagram at quarter filling consisting of Tomonaga Luttinger liquid, spin-gap state, channel-gap state, insulator, and phase separation is determined. We find that weak channel fluctuations stabilize the spin-gap state, while strong channel fluctuations lead to the transition to the insulator.
{"title":"Ground-state phase diagram of the one-dimensional \u0000t−Js−Jτ\u0000 model at quarter filling","authors":"Yuya Kurebayashi, Hiroki Oshiyama, N. Shibata","doi":"10.1103/PHYSREVB.103.165115","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.165115","url":null,"abstract":"We study the ground state of the one-dimensional \"$t$-$J_s$-$J_{tau}$ model\", which is a variant of the $t$-$J$ model with additional channel degree of freedom. The model is not only a generalization of the $t$-$J$ model but also an effective model of the two-channel Kondo lattice model in the strong coupling region. The low energy excitations and correlation functions are systematically calculated by the density matrix renormalization group (DMRG) method and the ground-state phase diagram at quarter filling consisting of Tomonaga Luttinger liquid, spin-gap state, channel-gap state, insulator, and phase separation is determined. We find that weak channel fluctuations stabilize the spin-gap state, while strong channel fluctuations lead to the transition to the insulator.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75453664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-10DOI: 10.1103/PHYSREVB.103.144414
Santanu Pal, Prakash C. Sharma, Hitesh J. Changlani, Sumiran Pujari
In the $XY$ regime of the $XXZ$ Heisenberg model phase diagram, we demonstrate that the origin of magnetically ordered phases is influenced by the presence of solvable points with exact quantum coloring ground states featuring a quantum-classical correspondence. Using exact diagonalization and density matrix renormalization group calculations, for both the square and the triangular lattice magnets, we show that the ordered physics of the solvable points in the extreme $XY$ regime, at $frac{J_z}{J_perp}=-1$ and $frac{J_z}{J_perp}=-frac{1}{2}$ respectively with $J_perp > 0$, adiabatically extends to the more isotropic regime $frac{J_z}{J_perp} sim 1$. We highlight the projective structure of the coloring ground states to compute the correlators in fixed magnetization sectors which enables an understanding of the features in the static spin structure factors and correlation ratios. These findings are contrasted with an anisotropic generalization of the celebrated one-dimensional Majumdar-Ghosh model, which is also found to be (ground state) solvable. For this model, both exact dimer and three-coloring ground states exist at $frac{J_z}{J_perp}=-frac{1}{2}$ but only the two dimer ground states survive for any $frac{J_z}{J_perp} > -frac{1}{2}$
{"title":"Colorful points in the XY regime of XXZ quantum magnets","authors":"Santanu Pal, Prakash C. Sharma, Hitesh J. Changlani, Sumiran Pujari","doi":"10.1103/PHYSREVB.103.144414","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.144414","url":null,"abstract":"In the $XY$ regime of the $XXZ$ Heisenberg model phase diagram, we demonstrate that the origin of magnetically ordered phases is influenced by the presence of solvable points with exact quantum coloring ground states featuring a quantum-classical correspondence. Using exact diagonalization and density matrix renormalization group calculations, for both the square and the triangular lattice magnets, we show that the ordered physics of the solvable points in the extreme $XY$ regime, at $frac{J_z}{J_perp}=-1$ and $frac{J_z}{J_perp}=-frac{1}{2}$ respectively with $J_perp > 0$, adiabatically extends to the more isotropic regime $frac{J_z}{J_perp} sim 1$. We highlight the projective structure of the coloring ground states to compute the correlators in fixed magnetization sectors which enables an understanding of the features in the static spin structure factors and correlation ratios. These findings are contrasted with an anisotropic generalization of the celebrated one-dimensional Majumdar-Ghosh model, which is also found to be (ground state) solvable. For this model, both exact dimer and three-coloring ground states exist at $frac{J_z}{J_perp}=-frac{1}{2}$ but only the two dimer ground states survive for any $frac{J_z}{J_perp} > -frac{1}{2}$","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85771561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-09DOI: 10.1103/PHYSREVRESEARCH.3.013019
C. Pappas, A. Leonov, L. Bannenberg, P. Fouquet, Thomas Wolf, F. Weber
We present a comprehensive investigation of the evolution of helimagnetic correlations in Mn$_{1-x}$Fe$_x$Si with increasing doping. By combining polarised neutron scattering and high resolution Neutron Spin Echo spectroscopy we investigate three samples with $x$=0.09, 0.11 and 0.14, i.e. with compositions on both sides of the concentration $x^* sim 0.11$ where the helimagnetic Bragg peaks disappear and between $x^*$ and the quantum critical concentration $x_C sim 0.17$, where $T_C$ vanishes. We find that the abrupt disappearance of the long range helical periodicity at $x^*$, does not affect the precursor fluctuating correlations. These build up with decreasing temperature in a similar way as for the parent compound MnSi. Also the dynamics bears strong similarities to MnSi. The analysis of our results indicates that frustration, possibly due to achiral RKKY interactions, increases with increasing Fe doping. We argue that this effect explains both the expansion of the precursor phase with increasing $x$ and the abrupt disappearance of long range helimagnetic periodicity at $x^*$.
{"title":"Evolution of helimagnetic correlations when approaching the quantum critical point of \u0000Mn1−xFexSi","authors":"C. Pappas, A. Leonov, L. Bannenberg, P. Fouquet, Thomas Wolf, F. Weber","doi":"10.1103/PHYSREVRESEARCH.3.013019","DOIUrl":"https://doi.org/10.1103/PHYSREVRESEARCH.3.013019","url":null,"abstract":"We present a comprehensive investigation of the evolution of helimagnetic correlations in Mn$_{1-x}$Fe$_x$Si with increasing doping. By combining polarised neutron scattering and high resolution Neutron Spin Echo spectroscopy we investigate three samples with $x$=0.09, 0.11 and 0.14, i.e. with compositions on both sides of the concentration $x^* sim 0.11$ where the helimagnetic Bragg peaks disappear and between $x^*$ and the quantum critical concentration $x_C sim 0.17$, where $T_C$ vanishes. We find that the abrupt disappearance of the long range helical periodicity at $x^*$, does not affect the precursor fluctuating correlations. These build up with decreasing temperature in a similar way as for the parent compound MnSi. Also the dynamics bears strong similarities to MnSi. The analysis of our results indicates that frustration, possibly due to achiral RKKY interactions, increases with increasing Fe doping. We argue that this effect explains both the expansion of the precursor phase with increasing $x$ and the abrupt disappearance of long range helimagnetic periodicity at $x^*$.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73630527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-08DOI: 10.1103/physrevb.102.245112
Sourav Chakraborty, S. Das, K. Pradhan
Being a wide band gap system GaMnN attracted considerable interest after the discovery of highest reported ferromagnetic transition temperature $T_C$ $sim$ 940 K among all diluted magnetic semiconductors. Later it become a debate due to the observation of either a ferromagnetic state with very low $T_C$ $sim$ 8 K or sometimes no ferromagnetic state at all. We address these issues by calculating the ferromagnetic window, $T_C$ Vs $p$, within a $t-t'$ Kondo lattice model using a spin-fermion Monte-Carlo method on a simple cubic lattice. We exploit the next-nearest-neighbor hopping $t'$ to tune the degree of delocalization of the free carriers and show that carrier localization (delocalization) significantly widen (shrunken) the ferromagnetic window with a reduction (enhancement) of the optimum $T_C$. We connect our results with the experimental findings and try to understand the ambiguities in ferromagnetism in GaMnN.
GaMnN作为一种宽带隙系统，在发现了所有稀释磁性半导体中最高的铁磁转变温度$T_C$ $ $sim$ 940k后，引起了人们的极大兴趣。后来成为一个争论由于铁磁态的观察与非常低的T_C sim 8 K美元美元或者有时没有铁磁态。我们通过在简单立方晶格上使用自旋费米子蒙特卡罗方法计算$t-t'$ Kondo晶格模型中的铁磁窗口$T_C$ Vs $p$来解决这些问题。我们利用次近邻跳跃$t'$来调整自由载流子的离域程度，并表明载流子的局部化(离域)显著地扩大(缩小)了铁磁窗口，减小(增强)了最优的$T_C$。我们将我们的结果与实验结果联系起来，并试图理解GaMnN中铁磁性的模糊性。
{"title":"Impact of next-nearest-neighbor hopping on ferromagnetism in diluted magnetic semiconductors","authors":"Sourav Chakraborty, S. Das, K. Pradhan","doi":"10.1103/physrevb.102.245112","DOIUrl":"https://doi.org/10.1103/physrevb.102.245112","url":null,"abstract":"Being a wide band gap system GaMnN attracted considerable interest after the discovery of highest reported ferromagnetic transition temperature $T_C$ $sim$ 940 K among all diluted magnetic semiconductors. Later it become a debate due to the observation of either a ferromagnetic state with very low $T_C$ $sim$ 8 K or sometimes no ferromagnetic state at all. We address these issues by calculating the ferromagnetic window, $T_C$ Vs $p$, within a $t-t'$ Kondo lattice model using a spin-fermion Monte-Carlo method on a simple cubic lattice. We exploit the next-nearest-neighbor hopping $t'$ to tune the degree of delocalization of the free carriers and show that carrier localization (delocalization) significantly widen (shrunken) the ferromagnetic window with a reduction (enhancement) of the optimum $T_C$. We connect our results with the experimental findings and try to understand the ambiguities in ferromagnetism in GaMnN.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85142716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mechanism underlying the enhancement of the Sommerfeld coefficient of quasiparticles at the first-order metamagnetic transition in UTe_2, reported by Miyake et al. in J. Phys. Soc. Jpn. 88, 063706 (2019), is discussed theoretically by taking into account the ferromagnetic order-parameter fluctuations on the basis of the Landau theory of phase transition. We find that the enhanced ferromagnetic spin fluctuation gives rise to the enhancement of the effective mass of the quasiparticles or the Sommerfeld coefficient gamma,which is consistent with the experimental observations. At the same time, the Kadowaki-Woods type scaling around the metamagnetic transition, reported by Imajo et this http URL J. Phys. Soc. Jpn. 88, 083705 (2019) and Knafo et al. in J. Phys. Soc. Jpn. 88, 063705 (2019), is also understood semi-quantitatively by assuming reasonable values of parameters of Landau-type free energy reproducing key quantities characterizing the metamagnetic transition.
UTe_2中准粒子在一阶变磁跃迁时Sommerfeld系数增强的机制，Miyake et al.发表于《J. Phys》。Soc。在朗道相变理论的基础上，考虑铁磁序参量波动，从理论上进行了讨论。Jpn. 88, 063706(2019)。我们发现，增强的铁磁自旋涨落导致准粒子的有效质量或索默菲尔德系数gamma的增强，这与实验观察结果一致。与此同时，围绕变磁跃迁的Kadowaki-Woods型尺度，由Imajo等人报道。Soc。[j] .物理学报，2016,38(1)，083705(2019)。Soc。Jpn. 88, 063705(2019)，也可以通过假设朗道型自由能参数的合理值来半定量地理解，再现表征变磁转变的关键量。
{"title":"On Sharp Enhancement of Effective Mass of Quasiparticles and Coefficient of T2 Term of Resistivity around First-Order Metamagnetic Transition Observed in UTe2","authors":"K. Miyake","doi":"10.7566/jpsj.90.024701","DOIUrl":"https://doi.org/10.7566/jpsj.90.024701","url":null,"abstract":"The mechanism underlying the enhancement of the Sommerfeld coefficient of quasiparticles at the first-order metamagnetic transition in UTe_2, reported by Miyake et al. in J. Phys. Soc. Jpn. 88, 063706 (2019), is discussed theoretically by taking into account the ferromagnetic order-parameter fluctuations on the basis of the Landau theory of phase transition. We find that the enhanced ferromagnetic spin fluctuation gives rise to the enhancement of the effective mass of the quasiparticles or the Sommerfeld coefficient gamma,which is consistent with the experimental observations. At the same time, the Kadowaki-Woods type scaling around the metamagnetic transition, reported by Imajo et this http URL J. Phys. Soc. Jpn. 88, 083705 (2019) and Knafo et al. in J. Phys. Soc. Jpn. 88, 063705 (2019), is also understood semi-quantitatively by assuming reasonable values of parameters of Landau-type free energy reproducing key quantities characterizing the metamagnetic transition.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82845496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-07DOI: 10.1103/PhysRevB.103.245132
Mainak Pal, Laetitia Bettmann, A. Kreisel, P. Hirschfeld
Correlated electron systems, particularly iron-based superconductors, are extremely sensitive to strain, which inevitably occurs in the crystal growth process. Built-in strain of this type has been proposed as a possible explanation for experiments where nematic order has been observed at high temperatures corresponding to the nominally tetragonal phase. Here we investigate a simple microscopic model of a strain-induced dislocation in the presence of electronic correlations, which create defect states that can drive magnetic anisotropy of this kind, if spin orbit interaction is present. Such defects can arise, e.g., in Fe-based systems or in Cu-O chains in cuprates. We estimate the contribution of these dislocations to magnetic anisotropy as detected by current torque magnetometry experiments.
{"title":"Magnetic anisotropy from linear defect structures in correlated electron systems","authors":"Mainak Pal, Laetitia Bettmann, A. Kreisel, P. Hirschfeld","doi":"10.1103/PhysRevB.103.245132","DOIUrl":"https://doi.org/10.1103/PhysRevB.103.245132","url":null,"abstract":"Correlated electron systems, particularly iron-based superconductors, are extremely sensitive to strain, which inevitably occurs in the crystal growth process. Built-in strain of this type has been proposed as a possible explanation for experiments where nematic order has been observed at high temperatures corresponding to the nominally tetragonal phase. Here we investigate a simple microscopic model of a strain-induced dislocation in the presence of electronic correlations, which create defect states that can drive magnetic anisotropy of this kind, if spin orbit interaction is present. Such defects can arise, e.g., in Fe-based systems or in Cu-O chains in cuprates. We estimate the contribution of these dislocations to magnetic anisotropy as detected by current torque magnetometry experiments.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78934732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-04DOI: 10.1103/PHYSREVRESEARCH.3.013271
H. Yi, Zengle Huang, W. Shi, L. Min, R. Wu, C. Polley, Ruoxi Zhang, Yi-Fan Zhao, Ling Zhou, J. Adell, X. Gui, W. Xie, M. Chan, Z. Mao, Zhijun Wang, Weida Wu, Cui-Zu Chang
(TaSe4)2I, a quasi-one-dimensional (1D) crystal, shows a characteristic temperature-driven metal-insulator phase transition. Above the charge density wave (CDW) temperature Tc, (TaSe4)2I has been predicted to harbor a Weyl semimetal phase. Below Tc, it becomes an axion insulator. Here, we perform angle-resolved photoemission spectroscopy (ARPES) measurements on the (110) surface of (TaSe4)2I and observe two sets of Dirac-like energy bands in the first Brillion zone, which agree well with our first-principles calculations. Moreover, we find that each Dirac band exhibits an energy splitting of hundreds of meV under certain circumstances. In combination with core level measurements, our theoretical analysis shows that this Dirac band splitting is a result of surface charge polarization due to the loss of surface iodine atoms. Our findings here shed new light on the interplay between band topology and CDW order in Peierls compounds and will motivate more studies on topological properties of strongly correlated quasi-1D materials.
{"title":"Surface charge induced Dirac band splitting in a charge density wave material \u0000(TaSe4)2I","authors":"H. Yi, Zengle Huang, W. Shi, L. Min, R. Wu, C. Polley, Ruoxi Zhang, Yi-Fan Zhao, Ling Zhou, J. Adell, X. Gui, W. Xie, M. Chan, Z. Mao, Zhijun Wang, Weida Wu, Cui-Zu Chang","doi":"10.1103/PHYSREVRESEARCH.3.013271","DOIUrl":"https://doi.org/10.1103/PHYSREVRESEARCH.3.013271","url":null,"abstract":"(TaSe4)2I, a quasi-one-dimensional (1D) crystal, shows a characteristic temperature-driven metal-insulator phase transition. Above the charge density wave (CDW) temperature Tc, (TaSe4)2I has been predicted to harbor a Weyl semimetal phase. Below Tc, it becomes an axion insulator. Here, we perform angle-resolved photoemission spectroscopy (ARPES) measurements on the (110) surface of (TaSe4)2I and observe two sets of Dirac-like energy bands in the first Brillion zone, which agree well with our first-principles calculations. Moreover, we find that each Dirac band exhibits an energy splitting of hundreds of meV under certain circumstances. In combination with core level measurements, our theoretical analysis shows that this Dirac band splitting is a result of surface charge polarization due to the loss of surface iodine atoms. Our findings here shed new light on the interplay between band topology and CDW order in Peierls compounds and will motivate more studies on topological properties of strongly correlated quasi-1D materials.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83223908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-02DOI: 10.1103/PHYSREVB.103.125137
M. Raczkowski, F. Assaad, M. Imada
Using a cluster extension of the dynamical mean-field theory (CDMFT) we map out the magnetic phase diagram of the anisotropic square lattice Hubbard model with nearest-neighbor intrachain $t$ and interchain $t_{perp}$ hopping amplitudes at half-filling. A fixed value of the next-nearest-neighbor hopping $t'=-t_{perp}/2$ removes the nesting property of the Fermi surface and stabilizes a paramagnetic metal phase in the weak-coupling regime. In the isotropic and moderately anisotropic regions, a growing spin entropy in the metal phase is quenched out at a critical interaction strength by the onset of long-range antiferromagnetic (AF) order of preformed local moments. It gives rise to a first-order metal-insulator transition consistent with the Mott-Heisenberg picture. In contrast, a strongly anisotropic regime $t_{perp}/tlesssim 0.3$ displays a quantum critical behavior related to the continuous transition between an AF metal phase and the AF insulator. Hence, within the present framework of CDMFT, the opening of the charge gap is magnetically driven as advocated in the Slater picture. We also discuss how the lattice-anisotropy-induced evolution of the electronic structure on a metallic side of the phase diagram is tied to the emergence of quantum criticality.
{"title":"Local moments versus itinerant antiferromagnetism: Magnetic phase diagram and spectral properties of the anisotropic square lattice Hubbard model","authors":"M. Raczkowski, F. Assaad, M. Imada","doi":"10.1103/PHYSREVB.103.125137","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.125137","url":null,"abstract":"Using a cluster extension of the dynamical mean-field theory (CDMFT) we map out the magnetic phase diagram of the anisotropic square lattice Hubbard model with nearest-neighbor intrachain $t$ and interchain $t_{perp}$ hopping amplitudes at half-filling. A fixed value of the next-nearest-neighbor hopping $t'=-t_{perp}/2$ removes the nesting property of the Fermi surface and stabilizes a paramagnetic metal phase in the weak-coupling regime. In the isotropic and moderately anisotropic regions, a growing spin entropy in the metal phase is quenched out at a critical interaction strength by the onset of long-range antiferromagnetic (AF) order of preformed local moments. It gives rise to a first-order metal-insulator transition consistent with the Mott-Heisenberg picture. In contrast, a strongly anisotropic regime $t_{perp}/tlesssim 0.3$ displays a quantum critical behavior related to the continuous transition between an AF metal phase and the AF insulator. Hence, within the present framework of CDMFT, the opening of the charge gap is magnetically driven as advocated in the Slater picture. We also discuss how the lattice-anisotropy-induced evolution of the electronic structure on a metallic side of the phase diagram is tied to the emergence of quantum criticality.","PeriodicalId":8511,"journal":{"name":"arXiv: Strongly Correlated Electrons","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86682966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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