41 citations · 203 across the 25 of their papers we have counts for
25 papers
Narrow-Sense Type-III Dirac Cones and Additional Flat Lines on a Honeycomb Lattice with Anisotropic Next-Nearest-Neighbor Hoppings
Keita Kishigi, Yasumasa Hasegawa
Critically tilted Dirac cones have attracted considerable attention because of their unconventional electronic properties in two-dimensional massless Dirac-fermion systems. Among t…
Crossover in Electronic Specific Heat near Narrow-Sense Type-III Dirac Cones
Keita Kishigi, Yasumasa Hasegawa
Two-dimensional massless Dirac fermions exhibit Dirac cones, which are classified into three types: type-I, type-II, and type-III. In both type-I and type-II cones, the energy disp…
Observable precursor of topological phase transition: temperature-dependent electronic specific heat in two-dimensional Dirac fermions
Keita Kishigi, Keita Tsukidashi, Yasumasa Hasegawa
Dirac points in two-dimensional massless Dirac fermions are topologically protected. Although single Dirac point cannot disappear solely, a pair of two Dirac points annihilates aft…
De Haas-van Alphen oscillations near the Lifshitz transition from two electron pockets to one electron pocket in the two-dimensional Dirac fermion systems
Keita Kishigi, Yasumasa Hasegawa
We theoretically study the de Haas-van Alphen (dHvA) oscillations in the system with changing the topology of the Fermi surface (the Lifshitz transition) by electron dopings. We em…
Enhancements of the 3/2 and 5/2 frequencies of de Haas-van Alphen oscillations near the Lifshitz transition in the two-dimensional compensated metal with overtilted Dirac cones
Keita Kishigi, Yasumasa Hasegawa
We study the de Haas-van Alphen (dHvA) oscillations in the two-dimensional compensated metal with overtilted Dirac cones near the Lifshitz transition. We employ the tight-binding m…
Energy quantization at the "three-quarter Dirac point" in a magnetic field
Yasumasa Hasegawa, Keita Kishigi
The quantization of the energy in a magnetic field (Landau quantization) at a three-quarter Dirac point is studied theoretically. The three-quarter Dirac point is realized in the s…