Chiral Orbital Currents in Quantum Materials

• Chiral orbital currents (COC) are chirality-resolved orbital motions that generate distinct orbital magnetic moments in materials like Mn3Si2Te6.
• They induce transport anomalies such as colossal magnetoresistance, topological Hall effects, and memristive behavior through symmetry breaking and orbital texture manipulation.
• The phenomena emerge from mechanisms like spin–orbit interactions, orbital Rashba effects, and chiral hybridization, offering diverse routes in interfaces, chiral structures, and superconductors.

Searching arXiv for recent and foundational papers on chiral orbital currents and closely related orbital-transport phenomena. Chiral orbital currents (COC) are orbital-current states or orbital-angular-momentum responses with a definite handedness. In the most direct real-space usage, the term denotes microscopic orbital currents circulating along crystallographic motifs and generating an orbital magnetic moment, as in ferrimagnetic Mn$_3$Si$_2$Te$_6$, where currents circulate along the edges of MnTe$_6$ octahedra in the $ab$-plane and induce a $c$-axis-oriented orbital moment below $T_C \sim 78$ K (Zhang et al., 2023). In the broader orbitronics literature, closely related uses of the term encompass helical orbital textures in reciprocal space, current-induced orbital accumulation, persistent-like orbital angular momentum currents in chiral helices, and spontaneous chiral edge currents in topological superconductors (Nikolaev et al., 2024, Cordova et al., 15 May 2026, Holmvall et al., 2023).

1. Terminology and scope

The phrase “chiral orbital current” is not restricted to a single microscopic realization. In correlated magnets it commonly refers to real-space loop currents with a definite circulation and an associated orbital magnetic moment. In interfacial orbitronics and chiral electronic structures it may instead denote nonequilibrium flows or accumulations of orbital angular momentum arising from orbital textures, orbital Rashba physics, or chirality-induced orbital selectivity. In chiral superconductors it is used for spontaneous equilibrium edge currents tied to broken time-reversal symmetry and nonzero Chern number (Zhang et al., 2023, Nikolaev et al., 2024, Cho et al., 9 Sep 2025, Holmvall et al., 24 Jan 2025).

Setting	Defining orbital object	Representative consequence
Mn$_3$Si$_2$Te$_6$	Loop currents along Te–Te edges of MnTe$_2$0 octahedra	CMR, current-sensitive Hall effect, THE, emergent inductance
Co/Al heterostructure	Large helical orbital texture at the interfacial Co layer	Orbital Edelstein effect and large current-induced torques
Chiral crystals, helices, and chiral potentials	Chirality-driven OAM texture or OAM-selective transmission	Orbital-momentum locking, orbital Edelstein response, orbital selectivity
Chiral superconductors	Spontaneous chiral edge current and orbital magnetic moment	Magnetic signatures of chiral order
Spin liquids and $_2$1-flux plaquettes	Spontaneous loop currents tied to chirality or flux	Orbital current order in insulating or bosonic phases

This range of usage suggests that COC is best understood as a family of chirality-resolved orbital-current phenomena rather than a single universal order parameter. A common thread is that orbital motion, rather than spin alone, becomes the primary degree of freedom controlling transport, magnetism, or spectroscopy.

2. Microscopic origin and symmetry conditions

In Mn$_2$2Si$_2$3Te$_2$4, COC are tied to noncollinear ferrimagnetic order and broken mirror and time-reversal symmetries. The currents run along Te–Te edges in the $_2$5-plane, and the resulting orbital moment $_2$6 points along the $_2$7-axis. The state is reported to be highly sensitive to small external currents and to be destabilized when the applied current crosses a critical threshold. Chemical substitution on the Te site with Se weakens the COC because the COC is developed due to spin-orbit interaction attributed to the tellurium atoms; with increasing Se content, the orbital current magnitude and $_2$8 decrease, while $_2$9 decreases from $_6$0 K at $_6$1 to $_6$2 K at $_6$3 (Zhang et al., 2022, Das et al., 12 Feb 2025).

A distinct route appears at broken-inversion interfaces. In Co/Al heterostructures, first-principles calculations identify a large helical orbital texture at the interfacial Co layer, attributed to the orbital Rashba effect caused by surface states at the Co/Al interface. The dominant matrix elements involve $_6$4, $_6$5, and $_6$6 orbitals, and the in-plane orbital texture remains strong without SOC, whereas SOC mainly adds a smaller out-of-plane component and higher-order winding. The current-induced orbital accumulation is expressed as

$_6$7

with the off-diagonal orbital magnetoelectric susceptibility $_6$8 maximized at the interfacial Co layer (Nikolaev et al., 2024).

Other works show that SOC is not universally required. In a single helical chain, chirality alone generates a momentum-dependent orbital-angular-momentum texture through Slater–Koster hybridization in the local basis $_6$9, without requiring atomic spin–orbit coupling. In that model the radial component vanishes identically, while the azimuthal and longitudinal components remain finite and reverse sign with handedness (Cordova et al., 15 May 2026). Structurally chiral crystals such as CoSi provide an analogous band-structure realization: the OAM, not the electron spin, is reported as the main driver of the nontrivial band topology, with a chirality-dependent sign of $_6$0 and monopole-like orbital-momentum locking even when SOC is negligible (Hagiwara et al., 2024, Brinkman et al., 2024).

In strongly correlated insulators, the relevant symmetry language is different but converges on the same theme. In square-lattice spin liquids that break time-reversal while preserving translation, nonzero scalar spin chirality,

$_6$1

implies spontaneous orbital charge currents in the bulk, although some current patterns appear only in a three-band formulation rather than a one-band model (Scheurer et al., 2018).

3. Mn$_6$2Si$_6$3Te$_6$4 as a prototypical real-space COC material

Mn$_6$5Si$_6$6Te$_6$7 is the canonical COC material in the current literature. Below $_6$8, an exotic quantum state emerges in which $_6$9-plane chiral orbital currents flow along the Te–Te edges of MnTe$ab$0 octahedra. At zero field, opposite-chirality domains are randomly distributed, so there is no net circulation and the resistance is high. A magnetic field applied along the hard $ab$1-axis selects a chirality, aligns domains, and produces colossal magnetoresistance, whereas $ab$2 gives only conventional or weakly modified behavior (Zhang et al., 2022, Zhang et al., 2023).

The coupling structure is central. The COC generate a $ab$3-axis orbital moment $ab$4, while the Mn moments lie primarily in the ferrimagnetic background. The net magnetic moment is described as a combination of both $ab$5 and the moments arising from the Mn atoms. This coupling is used to explain why the parent compound shows a $ab$6-order-of-magnitude reduction in $ab$7-plane resistivity under a hard-axis field and why the effect disappears when the COC state is melted by a small DC current exceeding a critical threshold (Zhang et al., 2022).

The current sensitivity is unusually strong. The COC state is reported as bistable and time dependent, with switching that mimics a first-order melting transition. At $ab$8 K, the critical current is stated to be about $ab$9–$c$0 mA, depending on field and temperature, and the switching delay ranges from seconds to minutes. Under $c$1, the transition becomes more robust and the voltage jump can become much larger; under $c$2, the transport evolution is continuous rather than bistable (Zhang et al., 2022).

Chemical substitution provides a controlled perturbation of the orbital sector. Replacing Te by Se weakens the spin–orbit interaction, shrinks the COC domains, and reduces $c$3. For $c$4, the CMR is reduced only moderately with increasing Se; for $c$5, the magnetoresistance becomes increasingly negative with Se content, consistent with weakening of the $c$6-axis orbital opposition and a larger net in-plane moment (Das et al., 12 Feb 2025).

4. Transport anomalies: Hall effect, topological Hall effect, inductance, and memory

Zhang et al. reported a current-sensitive Hall effect in the COC state of Mn$c$7Si$c$8Te$c$9 with three defining features: a sharp current-sensitive peak in $T_C \sim 78$0, an unusually large Hall angle reaching up to $T_C \sim 78$1, and a scaling relation

$T_C \sim 78$2

with $T_C \sim 78$3 in the fully developed COC state and $T_C \sim 78$4 when the COC is weakened or destroyed (Zhang et al., 2023). The anomaly appears for $T_C \sim 78$5 and not for $T_C \sim 78$6. The proposed interpretation is that a COC-induced internal field $T_C \sim 78$7 adds to the external field,

$T_C \sim 78$8

thereby enhancing the transverse force on carriers.

A related claim is that the topological Hall effect in the same material can be orbital rather than spin-texture driven. In that work, the Hall resistivity is decomposed as

$T_C \sim 78$9

with $_3$0 attributed predominantly to a COC contribution $_3$1 rather than to conventional chiral spin textures. The THE becomes stronger from bulk to nanoflakes, but disappears with increasing current together with the disappearance of the COC state, and its temperature and current dependence closely track the CMR (Das et al., 16 Dec 2025). This interpretation suggests that large Berry curvature and topological transport can arise purely from orbital degrees of freedom.

Beyond transverse transport, COC in Mn$_3$2Si$_3$3Te$_3$4 have been linked to circuit-like functionality. One study reports emergent inductance up to millihenry scale at low frequency and under $_3$5, with clockwise I–V loops attributed to first-order reconfiguration of coherent COC domains (Cao et al., 5 Sep 2025). A later work extends this to nonvolatile memristance: at higher frequency and low field, incomplete reversal and metastable trapping produce an intrinsic electromotive force and a finite remanent voltage at zero current, interpreted as orbital-state memory (Cao et al., 17 Apr 2026). In both cases the inductive or memristive response is described as intrinsic to the bulk crystal rather than to superconductivity or engineered nanostructures.

Orbital-current transport is not confined to Mn$_3$6Si$_3$7Te$_3$8. In hBN/graphene/hBN moiré superlattices, non-local transport measurements reveal a strong magnetic-field-induced chiral response stable up to room temperature, with sign reversal under magnetic-field reversal indicating the role of emerging orbital magnetic moments and orbital Hall transport (Salvador-Sánchez et al., 2022).

5. Orbitronic generation routes in interfaces, chiral structures, and phononic platforms

At metallic interfaces, COC-like responses arise from orbital texture rather than loop-current order. In Co/Al, a large helical orbital texture at the interfacial Co layer leads to a non-equilibrium orbital accumulation through the orbital Edelstein effect. Wannier-interpolated Kubo calculations identify a large $_3$9 at the interface and yield an effective field of about $_2$0 mT for realistic parameters, consistent with a large field-like torque. The broader significance is that light-element interfaces can support strong orbital responses without relying on heavy-metal SOC as the primary ingredient (Nikolaev et al., 2024).

A phononic route is provided by chiral surface acoustic waves. In light-metal/ferromagnet bilayers, chiral SAWs generate sizable orbital currents through the acoustic orbital Hall effect and acoustic orbital pumping. Symmetry analysis separates a vorticity-sensitive, magnetic-field-even AOHE signal from a magnetic-field-odd pumping signal. Strong responses are observed only in Ni|Cr and Ni|Ti, while Ni|Al and all cobalt-based bilayers show negligible responses, and SAW-driven orbital current generation exceeds electrically driven signals by an order of magnitude or more in the active materials (Rovirola et al., 9 Dec 2025).

Chiral molecular and helical systems provide a third route. A three-dimensional chiral electrostatic potential produces chirality-induced orbital selectivity through linear-orbital coupling, with the transmittance difference

$_2$1

reversing sign upon inversion of handedness, increasing with the length of the chiral region, and remaining robust against static disorder (Cho et al., 9 Sep 2025). DFT and real-time wave-packet simulations of a chiral molecular junction similarly show that mixing of carbon $_2$2 and $_2$3 channels by a chiral molecular orbital yields efficient generation of orbital current and long-range propagation along the carbon chain, in contrast to a Cu/O interface where the OAM is enhanced locally but rapidly quenched in bulk Cu (Kumari et al., 13 Feb 2025).

These results support a broad orbitronic picture in which chirality, broken inversion symmetry, or phonon vorticity generate orbital textures that are subsequently converted into transport, torque, or spin polarization. This suggests that the decisive control variable is often the orbital sector itself, with spin appearing as a secondary transduced degree of freedom.

6. Superconducting, bosonic, and correlated analogues, and the problem of detection

In chiral superconductors, spontaneous edge currents remain a major COC-related theme. Quasiclassical calculations for disc-shaped chiral $_2$4-wave superconductors show that mesoscopic finite-size effects dramatically enhance the total charge current and orbital magnetic moment, with a local maximum near $_2$5, $_2$6 scaling in large systems, and current reversal for $_2$7 (Holmvall et al., 2023). A later study shows that mesoscopic patterning can further amplify these currents: pentagons and hexagons yield the largest currents, disks generate large currents in the opposite direction, and the associated magnetic field is estimated as $_2$8–$_2$9 mT with an orbital magnetic moment approaching $_6$0 per Cooper pair (Holmvall et al., 24 Jan 2025).

Other many-body platforms realize orbital chirality without electronic solids. In square plaquettes pierced by $_6$1-flux, interacting bosons in the lowest band develop chiral orbital order formally equivalent to $_6$2-orbital bosons, producing a chiral vortex superfluid at weak coupling and a chiral Mott insulator at strong coupling; the effective low-energy Hamiltonian contains a $_6$3 term that favors the complex orbital $_6$4 (Liberto et al., 2021). In square-lattice spin liquids and doped antiferromagnets, spontaneous orbital currents are linked to scalar spin chirality, but whether currents appear depends on symmetry and on whether one works in a one-band or three-band formulation (Scheurer et al., 2018).

Detection methods are correspondingly diverse. In CoSi, circular dichroism in soft-X-ray ARPES reveals chirality-driven bulk OAM textures and motivates the intrinsic chiral circular dichroism

$_6$5

which isolates the handedness-dependent part of the photoemission response (Brinkman et al., 2024). For surface chiral metals, circularly polarized spin-selective ARPES has been proposed and applied to Sr$_6$6RuO$_6$7, where spin-resolved dichroic asymmetries up to $_6$8 for spin-down and $_6$9 for spin-up are reported as signatures reconcileable with spin-orbital chiral currents at the surface (Mazzola et al., 2024).

A persistent conceptual issue is that “COC” may refer to real-space loop currents, momentum-space OAM texture, projected OAM transport, or spontaneous edge current. This suggests that comparison across subfields requires care: SOC is essential in some systems, negligible in others; a finite OAM texture need not imply a finite projected linear-response OAM current, as shown in the single-helix model; and some claimed Hall or topological responses are explicitly presented as interpretations tied to orbital, rather than spin, emergent fields (Cordova et al., 15 May 2026, Das et al., 16 Dec 2025). The unifying theme is not a single microscopic mechanism, but the emergence of handed orbital motion as an experimentally active degree of freedom.