Thermal Drude weight signature of gapless quantum criticality: From interacting Kitaev topological superconductor to antiferromagnetic transverse-field Ising chain

Grüneisen ratio quest for self-duality of quantum criticality in a spin-1/2 XY chain with Dzyaloshinskii–Moriya interaction

“…in which the topological QPTs are demonstrated at U c =±1 with self-duality QCPs [13]. In fact, the above model only considers the symmetric spin-spin interaction responsible for the gapped topological phases with gapless quantum criticality [20]. In addition, the antisymmetric Dzyaloshinskii-Moriya (DM) interaction [21,22] as a result of spin-orbit coupling was introduced to explain the weak ferromagnetism in antiferromagnets, which, indeed, induces spin canting and favors the Tomonaga-Luttinger liquid (TLL) state with gapless low-lying excitation [23].…”

“…Herein, we focus on the XY spin model with DM interaction in a magnetic field. The thermal Drude weight is a good indicator signaling gapped (D th =0) or gapless (D th >0) behavior [20,34,35]. In the absence of magnetic field, the quantum critical lines by gap closing that separate the gapped topological and gapless TLL phases are identified, in which the topological to topological transition depends on the anisotropy parameter associated with a self-dual QCP, while the QCP signaling the transition from topological to TLL depends on the DM interaction without self-duality, implying a general QPT.…”