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Mohammad Javadi Balakan

Publications and source records attributed to Mohammad Javadi Balakan.

3 recordsLinked to original sources

Intrinsic magnetization of the superconducting condensate in Fe(Te,Se)

A spin-polarized superconducting condensate generates a net magnetization with measurable signatures. We present evidence for an intrinsic magnetic field in mesoscopic Fe(Te,Se) rings. The intrinsic field, encoded in the phase of superconducting quantum oscillations, scales linearly with the DC bias current, and its orientation exhibits an anomalous dependence on polarity and magnitude of the applied current. The magnetoresistance displays a dual flux-quantization effect with respect to the external magnetic field and the DC current. A minimal model incorporating Rashba coupling with an effective anisotropic out-of-plane interaction accounts for the experimental observations. These results provide evidence for spin-polarized superconductivity at the device scale and open new opportunities for superconducting spintronic and quantum information platforms.

cond-mat.supr-con↗

Aharonov-Bohm interference from coherent spin-polarized edge transport in Fe(Te,Se) superconducting rings

We report the coexistence of Aharonov-Bohm and Little-Parks oscillations in mesoscopic Fe(Te,Se) rings. The magnetoresistance shows two distinct periodicities: an $h/e$ component from ballistic edge interference and an $h/2e$ component from fluxoid quantization of Cooper pairs. Aharonov-Bohm oscillations persist deep into the superconducting phase, exhibit current-field symmetry, and follow a temperature dependence captured by a helical Luttinger liquid model, consistent with edge states in a topological superconductor.

cond-mat.supr-con↗

Observation of Half-Quantum Vorticity in an Iron-based Superconductor

Half-quantum vortices -- topological excitations carrying half the superconducting flux quantum -- are predicted to emerge in spin-triplet superconductors, where the spin component of order parameter enables fractional flux quantization. We present direct transport signatures of half-quantum vorticity in single-crystal Fe(Te,Se), an iron-based superconductor with helical Dirac surface states. Using mesoscopic superconducting ring devices, we observe half-integer quantum oscillations arising from the splitting of quantized fluxoid states, further supported by distinct signatures of trapped half-integer fluxoids. The quantum oscillations are modulated by a background symmetry, set by the relative orientation of the DC bias current and perpendicular magnetic field, consistent with strong spin-orbit coupling. These findings demonstrate the long-sought half-quantum vorticity in spin-polarized superconductors and open new directions toward non-Abelian excitations in quantum materials and scalable topological qubits.

cond-mat.supr-con↗