scholarly journals Mean-field phase diagram of two-dimensional electrons with disorder in a weak magnetic field

2003 ◽  
Vol 68 (15) ◽  
Author(s):  
I. S. Burmistrov ◽  
M. A. Baranov
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Weak Magnetic Field ◽  
Mean Field ◽  
Two Dimensional ◽  
Field Phase

The Magnetic Phase Diagram of High Tc Superconductors

MRS Bulletin ◽  
1990 ◽  
Vol 15 (6) ◽  
pp. 50-54 ◽  
Author(s):  
A.P. Malozemoff
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Phase Diagram ◽  
Magnetic Phase ◽  
Mean Field ◽  
Magnetic Phase Diagram ◽  
Transition Line ◽  
Type Ii ◽  
Field Phase ◽  
Type Ii Superconductor

Among the many surprises in the held of high temperature superconductivity, new features discovered in the magnetic phase diagram are among the most exciting and controversial, generating many new physical concepts and impacting practical applications. This brief review complements several other recent reviews and refers mostly to the bulk crystal (not ceramic) Y1Ba2Cu3O7 and Bi2Sr2Ca1Cu2Ox materials, from now on denoted YBaCuO and BiSrCaCuO.The magnetic phase diagram of a conventional type II superconductor as a function of magnetic held H and temperature T is well known and understood in the mean-field Ginzburg-Landau and London theories. As shown in Figure 1a, a Meissner phase characterized by complete flux exclusion appears at low fields, delineated by a mean-field phase transition line called the lower critical field Hc1(T), which increases linearly with decreasing temperature below Tc and then saturates at low temperature. A second mean-field phase transition line, called the upper critical field Hc2(T), delineates the transition between the normal and superconducting states and shows a T-dependence similar to Hc1(T). In a strongly type II superconductor (in which the penetration depth λ is much larger than the coherence length ξ), the large region intervening between Hc1 and Hc2 is called the Abrikosov mixed phase. Here magnetic field penetrates the superconductor in the form of tubes of magnetic field called flux lines or vortices. In an ideal isotropic superconductor, these vortices self-organize into a hexagonal array. Defects disturb the hexagonal long-range order, causing the array to break up into a kind of glassy state with more or less short-range order.

scholarly journals Universal behavior of the bosonic metallic ground state in a two-dimensional superconductor

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zhuoyu Chen ◽  
Bai Yang Wang ◽  
Adrian G. Swartz ◽  
Hyeok Yoon ◽  
Yasuyuki Hikita ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Quantum Phase Transitions ◽  
Metallic State ◽  
Two Dimensional ◽  
Metallic Behavior ◽  
Universal Behavior ◽  
Hall Resistivity ◽  
Wide Range ◽  
Metal State

AbstractAnomalous metallic behavior, marked by a saturating finite resistivity much lower than the Drude estimate, has been observed in a wide range of two-dimensional superconductors. Utilizing the electrostatically gated LaAlO3/SrTiO3 interface as a versatile platform for superconductor-metal quantum phase transitions, we probe variations in the gate, magnetic field, and temperature to construct a phase diagram crossing from superconductor, anomalous metal, vortex liquid, to the Drude metal state, combining longitudinal and Hall resistivity measurements. We find that the anomalous metal phases induced by gating and magnetic field, although differing in symmetry, are connected in the phase diagram and exhibit similar magnetic field response approaching zero temperature. Namely, within a finite regime of the anomalous metal state, the longitudinal resistivity linearly depends on the field while the Hall resistivity diminishes, indicating an emergent particle-hole symmetry. The universal behavior highlights the uniqueness of the quantum bosonic metallic state, distinct from bosonic insulators and vortex liquids.

scholarly journals THE ENERGY EIGENVALUES OF THE TWO DIMENSIONAL HYDROGEN ATOM IN A MAGNETIC FIELD

2006 ◽  
Vol 15 (06) ◽  
pp. 1263-1271 ◽  
Author(s):  
A. SOYLU ◽  
O. BAYRAK ◽  
I. BOZTOSUN
Keyword(s):  
Magnetic Field ◽  
Hydrogen Atom ◽  
Iteration Method ◽  
Weak Magnetic Field ◽  
The Other ◽  
Asymptotic Iteration Method ◽  
Iterative Approach ◽  
Two Dimensional ◽  
Energy Eigenvalues ◽  
The Magnetic Field

In this paper, the energy eigenvalues of the two dimensional hydrogen atom are presented for the arbitrary Larmor frequencies by using the asymptotic iteration method. We first show the energy eigenvalues for the case with no magnetic field analytically, and then we obtain the energy eigenvalues for the strong and weak magnetic field cases within an iterative approach for n=2-10 and m=0-1 states for several different arbitrary Larmor frequencies. The effect of the magnetic field on the energy eigenvalues is determined precisely. The results are in excellent agreement with the findings of the other methods and our method works for the cases where the others fail.

HIGH FIELD PHASE DIAGRAM OF THE FIELD-INDUCED SUPERCONDUCTING STATE OF λ-(BETS)2FeCl4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3101-3104
Author(s):  
L. BALICAS ◽  
J. S. BROOKS ◽  
K. STORR ◽  
S. UJI ◽  
M. TOKUMOTO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Superconducting State ◽  
Ground State ◽  
Electrical Transport ◽  
High Field ◽  
Two Dimensional ◽  
Exchange Field ◽  
Organic Conductor ◽  
Field Phase ◽  
Antiferromagnetic Ground State

We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor λ- (BETS) 2 FeCl 4. Below 4 K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41 T, and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe 3+ ions. We further argue that the Fe 3+ moments are essential to stabilize the resulting singlet, two-dimensional superconducting state. Here we provide experimental evidence indicating that this state, as well as the insulating antiferromagnetic ground state, is extremely sensitive to hydrostatic pressure.

Mean-field phase diagram of cold lattice bosons in disordered potentials

2007 ◽  
Vol 76 (1) ◽  
Author(s):  
P. Buonsante ◽  
V. Penna ◽  
A. Vezzani ◽  
P. B. Blakie
Keyword(s):  
Phase Diagram ◽  
Mean Field ◽  
Field Phase

scholarly journals Extension of the temperature-magnetic field phase diagram ofCeB6

2004 ◽  
Vol 69 (5) ◽  
Author(s):  
R. G. Goodrich ◽  
David P. Young ◽  
Donavan Hall ◽  
Luis Balicas ◽  
Z. Fisk ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Field Phase

η-PAIRING SUPERCONDUCTIVITY IN THE NEGATIVE-U HUBBARD MODEL: EFFECT OF FLUCTUATIONS AND DISORDER

1994 ◽  
Vol 08 (15) ◽  
pp. 2041-2058
Author(s):  
JÜRGEN STEIN
Keyword(s):  
Phase Diagram ◽  
Asymptotic Expansion ◽  
Hubbard Model ◽  
Strong Coupling ◽  
Mean Field ◽  
Higher Order ◽  
Field Phase ◽  
Effective Pair ◽  
The Mean ◽  
Pair Hopping

We have studied the influence of singular fluctuations around the mean-field solution as well as higher order contributions to the geometry controlled asymptotic expansion of the propagators on η-pairing superconductivity in the strong coupling negative-U Hubbard model in the presence of unpaired electrons. The modifications of the mean-field results due to the introduction of disorder and allowance for finite U are also calculated. Besides the singularities already present in the O(2) nonlinear σ-model we find a filling-depending singular depression of the repulsive effective pair-hopping interaction which strongly alters the mean-field phase diagram and appears to suppress the η-pairing phase near the band edges.

Transport in quasi-two-dimensional systems under a weak magnetic field

1995 ◽  
Vol 52 (3) ◽  
pp. 1984-1995 ◽  
Author(s):  
A. Cassam-Chenai ◽  
D. Mailly
Keyword(s):  
Magnetic Field ◽  
Weak Magnetic Field ◽  
Two Dimensional
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