Rich topological nodal line bulk states together with drum-head-like surface states in NaAlGe with anti-PbFCl type structure

2020-5
Wang, Xiaotian
Ding, Guangqian
Cheng, Zhenxiang
Surucu, Gokhan
Wang, Xiao-Lin
Yang, Tie
The band topology in condensed matter has attracted widespread attention in recent years. Due to the band inversion, topological nodal line semimetals (TNLSs) have band crossing points (BCPs) around the Fermi level, forming a nodal line. In this work, by means of first-principles, we observe that the synthesized NaAlGe intermetallic compound with anti-PbFCI type structure is a TNLS with four NLs in the k(z) = 0 and k(z) = pi planes. All these NLs in NaAlGe exist around the Fermi level, and what is more, these NLs do not overlap with other bands. The exotic drum-head-like surface states can be clearly observed, and therefore, the surface characteristics of NaAlGe may more easily be detected by experiments. Biaxial strain has been explored for this system, and our results show that rich TNL states can be induced. Furthermore, the spin-orbit coupling effect has little effect on the band structure of NaAlGe. It is hoped that this unique band structure can soon be examined by experimental work and that its novel topological elements can be fully explored for electronic devices.
Journal of Advanced Research

Suggestions

Enhanced second harmonic generation from coupled asymmetric plasmonic metal nanostructures
Yıldız, Bilge Can; Taşgın, Mehmet Emre; Abak, Musa Kurtuluş; Coskun, Sahin; Ünalan, Hüsnü Emrah; Bek, Alpan (IOP Publishing, 2015-12-01)
We experimentally demonstrate that two coupled metal nanostructures (MNSs), a silver nanowire and bipyramid, can produce similar to 30 times enhanced second harmonic generation compared to the particles alone. We develop a simple theoretical model, presenting the path interference effects in the nonlinear response of coupled MNSs. We show that the reason for such an enhancement can be the occurrence of a Fano resonance due to the coupling of the converter MNS to the long-lived mode of the attached MNS.
Novel topological nodal lines and exotic drum-head-like surface states in synthesized CsCl-type binary alloy TiOs
Wang, Xiaotian; Ding, Guangqian; Cheng, Zhenxiang; Surucu, Gokhan; Wang, Xiao-Lin; Yang, Tie (Elsevier BV, 2020-03-01)
Very recently, searching for new topological nodal line semimetals (TNLSs) and drum-head-like (DHL) surface states has become a hot topic in the field of physical chemistry of materials. Via first principles, in this study, a synthesized CsCl type binary alloy, TiOs, was predicted to be a TNLS with three topological nodal lines (TNLs) centered at the X point in the k(x/y/z) = pi plane, and these TNLs, which are protected by mirror, time reversal (T) and spatial inversion (P) symmetries, are perpendicular to...
Second harmonic generation in an asymmetric rectangular quantum well under hydrostatic pressure
Karabulut, Ibrahim; Atav, Ulfet; Safak, Haluk; Tomak, Mehmet (2007-04-30)
The effects of structure parameters and hydrostatic pressure oil the electronic states and the second harmonic generation (SHG) susceptibility of asymmetric rectangular quantum Well (ARQW) are studied. The asymmetry of the potential can be controlled by changing the structural parameters and this adjustable asymmetry is important for optimizing the SHG susceptibility. We have calculated analytically the electronic states in ARQW within the framework of the envelope function approach. Numerical results for A...
High-resolution multispectral satellite image matching using scale invariant feature transform and speeded up robust features
TEKE, Mustafa; Vural, M. Firat; Temizel, Alptekin; Yardimci, Yasemin (2011-09-23)
Satellite images captured in different spectral bands might exhibit nonlinear intensity changes at the corresponding spatial locations due to the different reflectance responses for these bands. This affects the image registration performance negatively as the corresponding features might have different properties in different bands. We propose a modification to the widely used scale invariant feature transform (SIFT) method to increase the correct feature matching ratio and to decrease the computation time...
New fuzzy extra dimensions from SU(N) gauge theories
Kürkcüoğlu, Seçkin (2015-07-16)
We start with an SU(N) Yang-Mills theory on a manifold M, suitably coupled to scalar fields in the adjoint representation of SU(N), which are forming a doublet and a triplet, respectively, under a global SU(2) symmetry. We show that a direct sum of fuzzy spheres S-F(2 Int) := S-F(2)(l) circle plus S-F(2)(l) circle plus S-F(2)(l + 1/2) circle plus S-F(2)(l - 1/2) emerges as the vacuum solution after the spontaneous breaking of the gauge symmetry and paves the way for us to interpret the spontaneously broken ...
Citation Formats
X. Wang, G. Ding, Z. Cheng, G. Surucu, X.-L. Wang, and T. Yang, “Rich topological nodal line bulk states together with drum-head-like surface states in NaAlGe with anti-PbFCl type structure,” Journal of Advanced Research, pp. 95–100, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/51486.