scholarly journals Role of Berry phase theory for describing orbital magnetism: From magnetic heterostructures to topological orbital ferromagnets

2016 ◽  
Vol 94 (12) ◽  
Author(s):  
J.-P. Hanke ◽  
F. Freimuth ◽  
A. K. Nandy ◽  
H. Zhang ◽  
S. Blügel ◽  
...  
Keyword(s):  
Berry Phase ◽  
Phase Theory ◽  
Orbital Magnetism ◽  
Magnetic Heterostructures ◽  
Berry Phase Theory

Vacuum induced berry phase: Theory and experimental proposal

2003 ◽  
Vol 50 (6-7) ◽  
pp. 1175-1181 ◽  
Author(s):  
Sougato Bose ◽  
Angelo Carollo ◽  
Ivette Fuentes-guridi ◽  
Marcelo França Santos ◽  
Vlatko Vedral
Keyword(s):  
Berry Phase ◽  
Phase Theory ◽  
Berry Phase Theory

Contribution of Pb to Ferroelectricity in Perovskite-type Oxides

2002 ◽  
Vol 748 ◽  
Author(s):  
Hiromu Miyazawa ◽  
Fumiyuki Ishii ◽  
Masaya Ishida ◽  
Eiji Natori ◽  
Tatsuya Shimoda ◽  
...  
Keyword(s):  
Stress Tensor ◽  
Berry Phase ◽  
Structural Phase ◽  
Covalent Bond ◽  
Electric Polarization ◽  
Covalent Bonds ◽  
Phase Theory ◽  
Additional Degree ◽  
Berry Phase Theory ◽  
Perovskite Type

ABSTRACTWe have studied the nature of the covalent bond between Pb 6s, 6p and O 2p orbitals in perovskites based on first-principles calculations. We conclude that the Pb 6p - O 2p covalent bond, not a bond involving Pb 6s, is crucial for the large ferroelectric effect in PbTiO3. The Pb 6s states behave like a shallow core level. To examine the effect of a Pb atom at the A site in the perovskite-type structure, we compared several calculated properties of PbTiO3 and BaTiO3 - the electric polarization, piezoelectric stress tensor and Young's modulus. The piezoelectric stress tensor e33 was calculated through Berry phase theory. BaTiO3 was found to have a larger e33 value than PbTiO3. In the case of BaTiO3, the response of Ti-O(2) to c-axis distortion is larger than in PbTiO3. We found that PbTiO3 is softer than BaTiO3 because of the cooperation of both Ti-O(2) and Pb-O(1) covalent bonds. We also found that the ferroelectric state is much softer than the paraelectric state. We propose that in the structural phase transition the system with the lower symmetry avoids ion repulsion through the additional degree of freedom available from atom displacement.

Vacuum induced Berry phase: theory and experimental proposal

2003 ◽  
Vol 50 (6-7) ◽  
pp. 1175-1181 ◽  
Author(s):  
Vlatko Vedral ◽  
Sougato Bose ◽  
Angelo Carollo ◽  
Ivette Fuentes-Guridi ◽  
Marcelo França Santos
Keyword(s):  
Berry Phase ◽  
Phase Theory ◽  
Berry Phase Theory

scholarly journals Berry Phase Theory of the Anomalous Hall Effect: Application to Colossal Magnetoresistance Manganites

1999 ◽  
Vol 83 (18) ◽  
pp. 3737-3740 ◽  
Author(s):  
Jinwu Ye ◽  
Yong Baek Kim ◽  
A. J. Millis ◽  
B. I. Shraiman ◽  
P. Majumdar ◽  
...  
Keyword(s):  
Hall Effect ◽  
Colossal Magnetoresistance ◽  
Berry Phase ◽  
Anomalous Hall Effect ◽  
Phase Theory ◽  
Berry Phase Theory

JAHN-TELLER EFFECT OF MOLECULAR COMPLEXES IN LIQUID SOLUTIONS

1994 ◽  
Vol 08 (21n22) ◽  
pp. 1319-1334 ◽  
Author(s):  
J.W. HALLEY ◽  
X.R. WANG
Keyword(s):  
Quantum Coherence ◽  
Berry Phase ◽  
Molecular Complexes ◽  
Liquid Solution ◽  
Teller Effect ◽  
Liquid Systems ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Molecular Dynamics Methods

We review recent work clarifying the sense in which the Jahn-Teller effect can exist in a molecular complex in liquid solution. We review the molecular dynamics methods for modeling such liquid systems using the cupric ion in aqueous solution as an example. We review the experimental evidence for the Jahn-Teller effect in liquids, emphasizing the importance of taking the time scale of the measurement into account. Finally we discuss the role of quantum coherence and the Berry phase in the Jahn-Teller effect.

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