Search query: Topological quantum phase transition

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abstract: A pressure induced topological quantum phase transition has been theoretically predicted for the semiconductor bismuth tellurohalide BiTeI with giant Rashba spin splitting. In this work, evolution of the electrical transport properties in BiTeI and BiTeBr is investigated under high pressure. The pressure dependent resistivity in a wide temperature range passes through a minimum at around 3 GPa, indicating the predicted topological quantum phase transition in BiTeI. Superconductivity is observed in both BiTeI and BiTeBr, while resistivity at higher temperatures still exhibits semiconducting behavior. Theoretical calculations suggest that superconductivity may develop from the multivalley semiconductor phase. The superconducting transition temperature, Tc increases with applied pressure and reaches a maximum value of 5.2 K at 23.5 GPa for BiTeI (4.8 K at 31.7 GPa for BiTeBr) followed by a slow decrease. The results demonstrate that BiTeX (X I, Br) compounds with nontrivial topology of electronic states display new ground states upon compression.
author_names: Yanpeng Qi

Wujun Shi

Pavel G Naumov

Nitesh Kumar

Raman Sankar

Walter Schnelle

Chandra Shekhar

F C Chou

Claudia Felser

Binghai Yan

Sergey A Medvedev
title: Topological Quantum Phase Transition and Superconductivity Induced by Pressure in the Bismuth Tellurohalide BiTeI.
venue: Advanced materials
year: 2017

abstract: ZrSiS has recently gained attention due to its unusual electronic properties: nearly perfect electron hole compensation, large, anisotropic magneto resistance, multiple Dirac nodes near the Fermi level, and an extremely large range of linear dispersion of up to 2 eV. We have carried out a series of high pressure electrical resistivity measurements on single crystals of ZrSiS. Shubnikov de Haas measurements show two distinct oscillation frequencies. For the smaller orbit, we observe a change in the phase of 0.5, which occurs between 0.16 0.5 GPa. This change in phase is accompanied by an abrupt decrease of the cross sectional area of this Fermi surface. We attribute this change in phase to a possible topological quantum phase transition. The phase of the larger orbit exhibits a Berry phase of pi and remains roughly constant up to 2.3 GPa. Resistivity measurements to higher pressures show no evidence for pressure induced superconductivity to at least 20 GPa.
author_names: Derrick VanGennep

Th Paul

C W Yerger

Samuel T Weir

Yogesh K Vohra

James J Hamlin
title: Possible pressure induced topological quantum phase transition in the nodal line semimetal ZrSiS
venue: Physical Review B
year: 2019

abstract: We report on the discovery of a quantum tri critical point (QTP) separating a line of first order topological quantum phase transitions from a continuous transition regime in a strongly correlated one dimensional lattice system. Specifically, we study a fermionic four leg ladder supporting a symmetry protected topological phase in the presence of on site interaction, which is driven towards a trivial gapped phase by a nearest neighbor interaction. Based on DMRG simulations, we show that, as a function of the interaction strength, the phase transition between the topological and the trivial phase switches from being continuous to exhibiting a first order character. Remarkably, the QTP as well as the first order character of the topological transition in the strongly correlated regime are found to clearly manifest in simple local observables.
author_names: Simone Barbarino

Giorgio Sangiovanni

Jan Carl Budich
title: First order topological quantum phase transition in a strongly correlated ladder
venue: Physical Review B
year: 2019

abstract: Since the seminal ideas of Berezinskii, Kosterlitz and Thouless, topological excitations have been at the heart of our understanding of a whole novel class of phase transitions. In most cases, those transitions are controlled by a single type of topological objects. There are, however, some situations, still poorly understood, where two dual topological excitations fight to control the phase diagram and the transition. Finding experimental realizations of such cases is thus of considerable interest. We show here that this situation occurs in BaCo2V2O8, a spin 1/2 Ising like quasi one dimensional antiferromagnet, when subjected to a uniform magnetic field transverse to the Ising axis. Using neutron scattering experiments, we measure a drastic modification of the quantum excitations beyond a critical value of the magnetic field. This quantum phase transition is identified, through a comparison with theoretical calculations, to be a transition between two different types of solitonic topological object, which are captured by different components of the dynamical structure factor.A neutron scattering study of an Ising like quasi one dimensional antiferromagnet, BaCo2V2O8, reveals a topological quantum phase transition when it is subjected to a transverse magnetic field.
author_names: Quentin Faure

Shintaro Takayoshi

Sylvain Petit

Virginie Simonet

S Raymond

L -P Regnault

Martin Boehm

Jonathan S White

Martin Mansson

Christian Ruegg

Pascal Lejay

Benjamin Canals

Thomas Lorenz

Shunsuke C Furuya

Thierry Giamarchi

Beatrice Grenier
title: Topological quantum phase transition in the Ising like antiferromagnetic spin chain BaCo2V2O8
year: 2017

abstract: We report a continuous phase transition between quantum anomalous Hall and trivial insulator phases in a magnetic topological insulator upon magnetization rotation. The Hall conductivity transits from one plateau of quantized Hall conductivity $e^2/h$ to the other plateau of zero Hall conductivity. The transition curves taken at various temperatures cross almost at a single point, exemplifying the critical behavior of the transition. The slope of the transition curves follows a power law temperature dependence with a critical exponent of 0.61$ This suggests a common underlying origin in the plateau transitions between the QAH and quantum Hall systems, which is a percolation of one dimensional chiral edge channels.
author_names: Minoru Kawamura

Masataka Mogi

Ryutaro Yoshimi

Atsushi Tsukazaki

Yusuke Kozuka

Kei S Takahashi

Masashi Kawasaki

Yoshinori Tokura
title: Topological quantum phase transition in magnetic topological insulator upon magnetization rotation
year: 2018

abstract: Topological insulators constitute a new phase of matter protected by symmetries. Time reversal symmetry protects strong topological insulators of the Z2 class, which possess an odd number of metallic surface states with dispersion of a Dirac cone. Topological crystalline insulators are merely protected by individual crystal symmetries and exist for an even number of Dirac cones. Here, we demonstrate that Bi doping of Pb1 xSnxSe (111) epilayers induces a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator. This occurs because Bi doping lifts the fourfold valley degeneracy and induces a gap at \bar \Gamma $G, while the three Dirac cones at the \bar{\rm M}$M points of the surface Brillouin zone remain intact. We interpret this new phase transition as caused by a lattice distortion. Our findings extend the topological phase diagram enormously and make strong topological insulators switchable by distortions or electric fields.Transitions between topological phases of matter protected by different symmetries remain rare. Here, Mandal et al. report a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator by doping Bi into Pb1 xSnxSe (111) thin films.
author_names: Partha Sarathi Mandal

Gunther Springholz

Valentine V Volobuev

Ondrej Caha

Andrei Varykhalov

Evangelos Golias

G Bauer

Oliver Rader

Jaime Sanchez-Barriga
title: Topological quantum phase transition from mirror to time reversal symmetry protected topological insulator
venue: Nature Communications
year: 2017

abstract: An attempt is made to understand the topological quantum phase transition, emergence of relativistic modes and local topological order of light in a strongly interacting light matter system. We study this system, in a one dimensional array of nonlinear cavities. Topological quantum phase transition occurs with massless excitation only for the finite detuning process. We present a few results based on the exact analytical calculations along with the physical explanations. We observe the emergence of massive Majorana fermion mode at the topological state, massless Majorana Weyl fermion mode during the topological quantum phase transition and Dirac fermion mode for the non topological state. Finally, we study the quantized Berry phase (topological order) and its connection to the topological number (winding number)
author_names: Sujit Sarkar
title: Topological Quantum Phase Transition and Local Topological Order in a Strongly Interacting Light Matter System
venue: Scientific Reports
year: 2017

abstract: When a quantum phase transition is crossed in finite time, critical slowing down leads to the breakdown of adiabatic dynamics and the formation of topological defects. The average density of defects scales with the quench rate following a universal power law predicted by the Kibble Zurek mechanism. We analyze the full counting statistics of kinks and report the exact kink number distribution in the transverse field quantum Ising model. Kink statistics is described by the Poisson binomial distribution with all cumulants exhibiting a universal power law scaling with the quench rate. In the absence of finite size effects, the distribution approaches a normal one, a feature that is expected to apply broadly in systems described by the Kibble Zurek mechanism.
author_names: Adolfo del Campo
title: Universal Statistics of Topological Defects Formed in a Quantum Phase Transition.
year: 2018

abstract: The quantum phase transition between two clean, non interacting topologically distinct gapped states in three dimensions is governed by a massless Dirac fermion fixed point, irrespective of the underlying symmetry class, and this constitutes a remarkably simple example of superuniversality. For a sufficiently weak disorder strength, we show that the massless Dirac fixed point is at the heart of the robustness of superuniversality. We establish this by considering both perturbative and nonperturbative effects of disorder. The superuniversality breaks down at a critical strength of disorder, beyond which the topologically distinct localized phases become separated by a delocalized diffusive phase. In the global phase diagram, the disorder controlled fixed point where superuniversality is lost, serves as a multicritical point, where the delocalized diffusive and two topologically distinct localized phases meet and the nature of the localization delocalization transition depends on the underlying symmetry class. Based on these features we construct the global phase diagrams of noninteracting, dirty topological systems in three dimensions. We also establish a similar structure of the phase diagram and the superuniversality for weak disorder in higher spatial dimensions. By noting that $1/r^2$ power law correlated disorder acts as a marginal perturbation for massless Dirac fermion in any spatial dimension $d$ we have established a general renormalization group framework for addressing disorder driven critical phenomena for fixed spatial dimension $d 2$
author_names: Pallab Goswami

Sudip Chakravarty
title: Superuniversality of topological quantum phase transition and global phase diagram of dirty topological systems in three dimensions
year: 2017

abstract: We investigate the quantum phase transition of the Su Schrieffer Heeger (SSH) model by inspecting the two site entanglements in the ground state. It is shown that the topological phase transition of the SSH model is signified by a nonanalyticity of local entanglement, which becomes discontinuous for finite even system sizes, and that this nonanalyticity has a topological origin. Such a peculiar singularity has a universal nature in one dimensional topological phase transitions of noninteracting fermions. We make this clearer by pointing out that an analogous quantity in the Kitaev chain exhibiting the identical nonanalyticity is the local electron density. As a byproduct, we show that there exists a different type of phase transition, whereby the pattern of the two site entanglements undergoes a sudden change. This transition is characterised solely by quantum information theory and does not accompany the closure of the spectral gap. We analyse the scaling behaviours of the entanglement in the vicinities of the transition points.
author_names: Jaeyoon Cho

Kun Woo Kim
title: Quantum Phase Transition and Entanglement in Topological Quantum Wires
venue: Scientific Reports
year: 2017